Terms beginning with a capital letter have the meaning defined in Table 1. Terms beginning with a small letter have the meaning commonly defined for the context in which they are used. For instance, Table 1 defines Object, Scene, and User but does not define object, scene, and human.
A dash “-” preceding a Term in Table 1 means the following:
- If the font is normal, the Term in the table without a dash and preceding the one with a dash should be placed before that Term. The notation is used to concentrate in one place all the Terms that are composed of, e.g., the word Decentralised followed by one of the words Application, Autonomous Organisation, Finance, System, and User Identifier, or definitions belonging to the same class, e.g., Action and Items.
- If the font is italic, the Term in the table without a dash and preceding the one with a dash should be placed after that Term. The notation is used to concentrate in one place all the Terms that are composed of, e.g., the word Interface preceded by one of the words Brain-Computer, Haptic, Speech, and Visual.
Table 1 – General Terms and Definitions
|An Item that uniquely references a Registered human.
|A Functionality provided by a Process.
|The Action of requesting that a Service confirm that an Entity is what it claims to be.
|The Action of Calling a Service to obtain an Entity with associated OutRights to Act on the Entity.
|The Action of requesting that a Service modify the Rights of a User and provide OutRights, e.g., to further Change the Rights.
|The Action of requesting that a Service change the Format of the Data of an Item into a Format specified by a FormatID.
|The Action of requesting that a Service provide a DiscoveryOut Item containing:
1. The IDs of the Items relevant to the User’s request to Discover expressed in the DiscoverIn Item
2. The OutRights to Act on the DiscoverOut Item.
|The Action of requesting that a Process execute a Contract.
|The Action of requesting that a Service make the ID of an Item unavailable and provide OutRights, e.g., to make the ID available again.
|The Action of requesting that a Service produce an Item from Data & Metadata.
|The Action of a User requesting that a Service read Data & Metadata stored at an Address.
|The Action of requesting that a Service provide an InformOut Item containing information about an InItem, such as the Metadata of the InItem, with the OutRights to Act on the InformOut Item.
|The Action of requesting that a Service provide an InterpretOut Item containing interpretation of an InItem, such as translation or extraction of Personal Status, with the OutRights to Act on the InterpretOut Item.
|The Action of requesting that a Service add an Entity at an M-Location with a Spatial Attitude and provide OutRights to Act on the MM-Added Entity.
|The Action of requesting that a Service change the features of a Model MM-Embedded at an M-Location with a Stream and provide the OutRights to Act on the MM-Added Entity.
|The Action of requesting that a Service stop MM-Enabling selected Entities Embedded at an M-Location and provide OutRights to Act on the MM-Disabled Entities.
|The Composite Action of requesting that a Service MM-Add and MM-Enable an Entity either located at a Service or at an M-Location at a destination M-Location with a Spatial Attitude and provide OutRights to Act on the MM-Embedded Entity.
|The Action of requesting that a Service accept requests to MM-Send selected Entities MM-Added at an M-Location or to MM-Embed those selected Entities at a destination M-Location and provide OutRights to act on the M-Entities.
|The Action of requesting that a Process forward an Item or Data/Metadata to a Process with appropriate granting Rights.
|The Action of requesting that a Service produce a new Item from an existing Item by providing new Data and Metadata with the OutRights to further Act on the new Item.
|The Action of requesting that a Device present an Entity available at a Device to a U-Location as Media with a Spatial Attitude.
|The Composite Action of requesting that:
1. A Service MM-Send selected Entities Embedded at an M-Location to a Device.
2. The Device MU-Actuate at a U-Location with a Spatial Attitude the Entity received.
|The Action of requesting that a Process transmit an Item to a Device or store an Item at an Address.
|The Action of requesting that a Marketplace include an Asset to its repertory of Assets.
|The Action of a human requesting that an M-Instance grant their Users the Rights to perform Actions in the M-Instance.
|The Action of requesting that a Service forward a Request-Action or a Response-Action to a Resolution Service in another M-Instance.
|The Composite Action of requesting that a Service:
1. MM-Embed a Model at an M-Location with a Spatial Attitude.
2. MU-Animate the Model MM-Embedded at an M-Location.
3. MU-Render specified Entities at the M-Location to a U-Location.
|The Action of a User1 requesting that a Service:
1. Assign Rights on an Asset to User2 (“buyer”).
2.1. Wallet1 of User1 (“seller”) to be increased by Value1.
2.2. Wallet2 of User2 to be decreased by Value2.
Wallet3 of the Service enabling/facilitating the Transaction to be increased by Value3 (optionally).
|The Composite Action of a User requesting:
1. A Device to
1.1. UM-Capture an animation stream extracted from a scene at a U-Location.
1.2. UM-Send the animation stream and Metadata to a User.
2. A Service to Identify the Animation Stream.
3. A Service to MM-Animate the Model MM-Embedded at the M-Location using the Animation Stream.
|The Action of requesting that a Device capture Media from a scene at a U-Location.
|The Composite Action of a User requesting:
1. A Device to:
1.1. UM-Capture a scene at U-Location.
1.2. MM-Send Data and Device-provided Metadata to a User.
2. A Service to:
2.1. Identify an Entity from UM-Sent Data and Metadata.
2.2. MM-Embed the Entity at an M-Location with a Spatial Attitude.
|The Action of a Device acquiring Data & Metadata from an Address.
|The Action of requesting that a Service verify that a Process has the Rights to perform or request a Process to perform an Action on an Item.
|A rendered User (synonym of Persona).
|A shared immutable ledger stored on a peer-to-peer network of computers.
|The attestation that a Process or Item has specified characteristics.
|Connected Autonomous Vehicle
|(CAV) A vehicle able to autonomously reach a U-Location by using its own sensing and processing capabilities to generate an M-Instance, sharing its M-Instance with other CAVs and issuing actuation commands.
|The process of changing the Format of Data.
|Information represented in digital form.
|The syntax and semantics of Data.
|The combination of Data and Metadata that is not (yet) an Item.
|Data used in Actions and Items.
|The URL of a storage facility.
|A number expressing a Value in a Currency.
|– Cognitive State
|The representation of a User’s Personal Status that reflects the way they understand the environment, such as “Confused”, “Dubious”, “Convinced”.
|A set of numbers representing a Position in a Metaverse environment using a coordinate system.
|A medium of exchange enabling Transactions in a Metaverse environment.
|The representation of a User’s Personal Status that results from their interaction with an environment, such as “Angry”, “Sad”, “Determined”.
|The set of the 3 roll, pitch, yaw angles indicating the rotation around the principal axis (x) of an Object, its y axis having an angle of 90˚ counterclockwise (right-to-left) with the x axis and its z axis (pointing up toward a viewer viewing from above).
|– Personal Status
|The representation of the information internal to a User characterising their behaviour.
|A point in an M-Environment identified by the set of local Coordinates.
|– Point of View
|The Spatial Attitude of a Persona watching an Environment.
|The Coordinates of a point in a Metaverse Environment using a Coordinate system.
|– Social Attitude
|The representation of a User’s Personal Status related to the way it intends to position vis-à-vis an environment, e.g., “Respectful”, “Confrontational”, “Soothing”.
|– Spatial Attitude
|The Position and Orientation of an Entity, and their velocities and accelerations.
|The representation of the measure of time.
|(dApp) A Process that runs on a decentralised computing system.
|– Autonomous Organisation
|(DAO) An organisation without centralised leadership, where the main governing rules are typically encoded by means of a Smart Contract.
|(DeFi) A financial technology based on a secure infrastructure of distributed ledgers like those used by crypto currencies.
|A set of dApps enabling a group of Users to make decisions without a centralised entity.
– A U-Environment to interact with an M-Instance and/or
– An M-Instance to interact with a U-Environment.
|A moral or legal obligation to act or behave.
|The state of a User having certain Rights in an M-Instance.
|A Functionality that is expected to be provided by an entity.
|Either a Digitised or a Virtual Human.
|The digital representation of a human.
|A computer-created Object that has a human appearance when rendered but is not a Digitised Human.
|The action or manner of directing and controlling actors of the Metaverse Ecosystem.
|Information and Communication Technologies
|(ICT) Technologies that enable the processing and distribution of information via the network.
|A communication pathway enabling systems to interact.
|(BCI) A communication pathway that allows a human to interact with an M-Instance by sensing and processing the electrical activity of the brain.
|A communication pathway that allows a human to interact with an M-Instance through bodily movements and sensations.
|A communication pathway that allows a human to interact with an M-Instance using spoken language.
|A communication pathway that allows a human to interact with an M-Instance through bodily movements and visual messages.
|The ability of an M-Instance to exchange and make use of the data of another M-Instance.
|Data and Metadata supported and identified by an M-Instance.
|An Item that uniquely references a human who has Registered. A User may have more than one Account with one or more Services.
|– Activity Data
|An Item containing the record of all the Actions made by a User.
|An Item that may be the object of a Transaction. It may be MM-Embedded at an M-Location or Posted to a Service.
|An Item containing:
1. The Entity or the ID of the Entity to be Authenticated.
2. Information related to the rendering of AuthenticateOut.
|An Item containing the result of processing the Request-Authenticate Action and its rendering.
|A Program and its Metadata stored on a Device. It is activated by an external entity, e.g., a User, or another activated Contract.
|An Item containing:
1. A description of the Items to be Discovered.
2. Information related to the rendering of DiscoverOut.
|An Item containing the description of the Items Discovered and information related to its rendering.
|Any of the following Items that can be MU-Rendered: Object, Model, Scene, Event, and Experience.
|An Entity that includes selected Entities at an M-Location and their Animations during a period.
|An Entity comprising User-selected Entities of an Event and the User Interactions with the Entities of the Event.
|An Item that uniquely references an Item in an M-Instance.
|An Item containing:
1. A description of the Item about which information is requested.
2. Information related to the rendering of InformOut.
|An Item containing the description of the Item object of an InformIn.
|An Item containing the Request-Action issued by a User on an Entity at an M-Locations and the corresponding Times.
|An Item containing:
1. The ID or the Item to be Interpreted.
2. Information related to the rendering of InterpretOut.
|An Item containing the description of the Item object of an InterpretIn Item.
|An Item containing a list of Transactions involving Assets.
|An Item containing a structure establishing a correspondence between U-Locations with M-Locations.
|An Identified subset of an M-Instance.
|An Item containing application-specific Data MM-Sent by a Source Process to a Destination Process.
|An implementation of the Common Metaverse Specifications.
|An Identified delimited space of an M-Environment.
|An Object representing an object with its features ready to be MM-Animated or UM-Animated.
|An Item with at least one of Audio, Visual, or Haptic perceptibility attributes.
|An Item expressing the promise of a Process to perform Actions on Items at M-Locations during a Time.
|A Model representing a human.
|– Personal Profile
|An Item containing the Data about the human represented by a User.
|Data that can be executed
|The Ledger associated with a specific Asset.
|An Item of the request to a Process to perform an Action as defined in this document.
|An Item containing the response of a Process to a Request-Action as defined in this document.
|An Item expressing the Process’s authorisation to perform Actions on Items at M-Locations during a Time.
|An Item expressing the terms and conditions under which a User operates in an M-Instance or M-Environment.
|A possibly hierarchical Composition of Objects having Spatial Attitudes.
|– Social Graph
|A representation of a User’s network of connections with Items, M-Locations, and Processes.
|An Item made by a continuous flow of Data.
|Item representing the changed state of the Accounts and the Rights of a seller User and a buyer User on an Asset and optionally of the Service facilitating/enabling the Transaction
|An identifiable delimited portion of the Universe.
|– Personal Data
|An Item containing Activity Data, Personae, and Social Graph of a User.
|An Amount and the Currency with which the Amount is expressed.
|A container of Currency units. In general, a Wallet is implemented outside of the M-Instance.
|A subdivision of a Profile indicating the completeness of the user experience provided by the Profile.
|1. Data acquired by a Device using a Sensor.
2. Data converted by a Device from an Item to a format that can be presented.
|An attribute of Data, e.g., of a human, a Process, an M-Location, a U-Location, or an Item.
|(M-Instance) A set of Processes providing some or all the following functions:
1. To sense data from U-Locations.
2. To process the sensed data and produce Data.
3. To produce one or more M-Environments populated by Objects that can be either digitised or virtual, the latter with or without autonomy.
4. To process Objects from the M-Instance or potentially from other M-Instances to affect U- and/or M-Environments using Objects in ways that are:
4.1. Consistent with the goals set for the M-Instance.
4.2. Effected within the capabilities of the M-Instance.
4.3. Complying with the Rules set for the M-Instance and applicable laws.
|A component of a Device able to MU-Render an Entity and environment Data to a U-Environment.
|An Item Embedded at an M-Location or Posted to a Service that may be the object of a Transaction.
|The ensemble of entities and rules ensuring that Metaverse Instances operate in the interest of Metaverse Stakeholders.
|– Enabling Service Layer
|The set of Services such as payment, security, identity, privacy, etc. that enable operation of an M-Instance.
|Any of the following Items that can be MU-Rendered: Scene, Object, Model, Event, and Experience.
|(M-Environment) A portion of an M-Instance run by a Registration system.
|– Experience Layer
|The set of functions, such as Devices, that generate Experiences.
|The attribute of a Process of being endowed with the capability of performing particular Action(s).
|The collection of players that support the design, development, deployment, operation, and content and service provisioning to Metaverse Instances.
|(M-Instance) An implementation providing all or a subset of the Metaverse Functionalities.
|The ability of M-Instance #1 to use data from and as intended by M-Instance #2. Interoperability can be Direct or Mediated by a Conversion Service.
|– Infrastructure Layer
|The set of functions such as network, transport, storage, and (cloud, edge) processing that enable an M-Instance to operate.
|Metaverse-specific Data that may include Metadata that may include Rights.
|A subdivision of a Profile that indicates the degree of completeness of the user experience provided by that Level.
|(M-Location) An identifiable delimited portion of the Metaverse.
|The entity overseeing the operation of an M-Instance.
|– Operation Model
|The components and sequence of steps involved in an M-Instance provids Functionalities.
|The entity overseeing the operation of an M-Environment.
|A User participating in activities of a Metaverse Operator (i.e., a business customer of an Operator)
|– Platform Layer
|The set of Services, such as content creation, content discovery, and content access functions that enable an M-Instance to operate.
|The instance of a program being executed.
|A recognised subset of the Functionalities (Functionality Profile) or Technologies (Technology Profile) specified by the Common Metaverse Specifications.
|A Device able to UM-Capture a scene and other environment information as Data.
|The collection of standards specifying the Technologies and Technology Profiles enabling Metaverse Interoperability.
|An entity performing a function aimed at achieving a goal in an M-Instance.
|The set of values and stored data of an M-Instance at a given time.
|A Technology or group of Technologies enabling an M-Instance to provide a Functionality.
|A structured application of scientific and/or technical methods that supports a Functionality.
|One or a set of Processes representing a human.
|The digital representation of an object or a computer-generated Object that can be rendered to and perceived by a human ear.
|A Virtual Object animated by a Process giving it the ability to act (e.g., move, speak, respond, execute) with a degree of autonomy.
|An Object that includes more than one Object Type.
|A Digitised or a Virtual Object.
|The digital representation of an object.
|An Object with the haptic features of an object able to be rendered to provide haptic sensations in a human.
|An Object representing a human.
|The digital representation of a sound emitted by the vocal tract of a human or generated by a computer with similar audio characteristics.
|One of Audio, Visual, Haptic, Olfaction, and Gustation.
|A computer-generated Object that is not a Digitised Object.
|The digital representation of an object captured by an electromagnetic or high-frequency audio signal or computer-generated that can be rendered to and perceived by a human eye.
|A Service providing information from a U-Environment to a Blockchain.
|The Rights of a User to keep their Personal Profile secret.
|An application-specific Program executed on a Device.
|The characteristics of a Process.
|A Process able to:
1. UM-Capture Data from a U-Location
2. UM-Send Data and Metadata to a User.
1. MM-Send an Entity from an M-Location to the Device.
2. MU-Render an Entity at a U-Location.
|A Process that can be called to provide specific Functionalities.
|A Process representing a human that is UM-Animated by a Stream or MM-Animated by an autonomous agent.
|An application-specific Program executed on a Device.
|A Process representing a UM-Captured human as a Persona that are either UM-Animated by a Stream or MM-Animated by an autonomous agent.
|A set of base standards and/or their subsets.
|The set of Functionalities offered by a Metaverse Profile.
|The set of Technologies offered by a Metaverse Profile.
|The provisioning by a human of a subset of Personal Data to an M-Instance/Environment to obtain an Account.
|The process of making an Item perceptible by human senses.
|Data that represent an entity of a U-Environment in an M-Instance.
|The subjective awareness of being able to decide, execute, and control one’s own actions in an M-Environment.
|The engagement of senses to form a complete M-Instance Experience.
|The feeling of being in an M-Instance with other Digital Humans for real.
|A Service converting the Data produced by an M-InstanceA into Data understood and acted upon by M-InstanceB as intended by M-InstanceA.
|A Program stored on a Blockchain that runs when activated by an external entity, e.g., a User or another Smart Contract.
|A representation of an Asset that is interchangeable with other Assets of the same type.
|(NFT) A unique digital identifier of an Asset that:
– Cannot be copied (i.e., a copy is known to be a copy), substituted, or subdivided.
– Is recorded in a digital ledger.
– Is used to certify Object authenticity and ownership.
|A system allowing a User to make reliable Transactions without trusting or knowing the parties the User makes Transactions with.
|The physical world.
|(U-Location) An identifiable delimited portion of the Universe.
|An example of how an application domain can be supported by an M-Instance/Environment.
|The pair of public and private keys where the public key is used to encrypt, and the private key is used to both encrypt and decrypt Data.
|An Identifier that enables the verifiable association with a User without requiring a centralised registry.
|A Decentralised Identifier derived from the User’s Public Key owned and managed directly by the User based on the knowledge of their own Private Key, e.g., stored in the Crypto Wallet enabled by the Blockchain underpinning the Metaverse Instance.
|Software or hardware holding the Public and Private Keys of a User to enable them to make Transactions by accessing their Account on a Blockchain.
The Terms used in this standard whose first letter is capital and are not already included in Table 1 are defined in Table 24. To concentrate in one place all the Terms that are composed of a common name followed by other words (e.g., the word Data followed by one of the words Format, Type, or Semantics), the definition given to a Terms preceded by a dash “-” applies to a Term composed by that Term without the dash preceded by the Term that precedes it in the column without a dash.
Table 24 – MPAI-wide Terms
|Static or slowly changing data that are required by an application such as domain knowledge data, data models, etc.
|AI Framework (AIF)
|The environment where AIWs are executed.
|AI Model (AIM)
|A data processing element receiving AIM-specific Inputs and producing AIM-specific Outputs according to according to its Function. An AIM may be an aggregation of AIMs.
|AI Workflow (AIW)
|A structured aggregation of AIMs implementing a Use Case receiving AIW-specific inputs and producing AIW-specific outputs according to the AIW Function.
|An MPAI Standard designed to enable a particular application domain.
|A connection between an output port of an AIM and an input port of an AIM. The term “connection” is also used as synonymous.
|The infrastructure that implements message passing between AIMs.
|One of the 7 AIF elements: Access, Communication, Controller, Internal Storage, Global Storage, Store, and User Agent
|An AIM aggregating more than one AIM.
|One of the 7 AIF elements: Access, Communication, Controller, Internal Storage, Global Storage, Store, and User Agent
|The attribute of an Implementation of being a correct technical Implementation of a Technical Specification.
|The normative document specifying the Means to Test the Conformance of an Implementation.
|– Testing Means
|Procedures, tools, data sets and/or data set characteristics to Test the Conformance of an Implementation.
|A channel connecting an output port of an AIM and an input port of an AIM.
|A Component that manages and controls the AIMs in the AIF, so that they execute in the correct order and at the time when they are needed
|Information in digital form.
|The standard digital representation of Data.
|An instance of Data with a specific Data Format.
|The meaning of Data.
|Coded representation of a text, audio, speech, or visual feature.
|Data corresponding to and representing a physical entity.
|The ensemble of actors making it possible for a User to execute an application composed of an AIF, one or more AIWs, each with one or more AIMs potentially sourced from independent implementers.
|The ability to trace the output of an Implementation back to the inputs that have produced it.
|The attribute of an Implementation whose extent of applicability can be assessed by making the training set and/or network open to testing for bias and unanticipated results.
|The operations effected by an AIW or an AIM on input data.
|A Component to store data shared by AIMs.
|A Component to store data of the individual AIMs.
|A name that uniquely identifies an Implementation.
|1. An embodiment of the MPAI-AIF Technical Specification, or
2. An AIW or AIM of a particular Level (1-2-3) conforming with a Use Case of an MPAI Application Standard.
|A legal entity implementing MPAI Technical Specifications.
|A unique name assigned by the ImplementerID Registration Authority to an Implementer.
|ImplementerID Registration Authority (IIDRA)
|The entity appointed by MPAI to assign ImplementerID’s to Implementers.
|Instance of a class of Objects and the Group of Objects the Instance belongs to.
|The ability to functionally replace an AIM with another AIW having the same Interoperability Level
|The attribute of an AIW and its AIMs to be executable in an AIF Implementation and to:
1. Be proprietary (Level 1)
2. Pass the Conformance Testing (Level 2) of an Application Standard
3. Pass the Performance Testing (Level 3) of an Application Standard.
|Structured and/or unstructured information made accessible to AIMs via MPAI-specified interfaces
|A sequence of Records transported by Communication through Channels.
|The set of attributes of a technology or a set of technologies specified by the applicable parts of an MPAI standard.
|The attribute of an Implementation of being Reliable, Robust, Fair and Replicable.
|The normative document specifying the Means to Assess the Grade of Performance of an Implementation.
|– Assessment Means
|Procedures, tools, data sets and/or data set characteristics to Assess the Performance of an Implementation.
|An entity Assessing the Performance of an Implementation.
|A particular subset of the technologies used in MPAI-AIF or an AIW of an Application Standard and, where applicable, the classes, other subsets, options and parameters relevant to that subset.
|A data structure with a specified structure
|The AIMs and theirs Connections in an AIW.
|A technically correct software implementation of a Technical Specification containing source code, or source and compiled code.
|The attribute of an Implementation that performs as specified by the Application Standard, profile, and version the Implementation refers to, e.g., within the application scope, stated limitations, and for the period of time specified by the Implementer.
|The attribute of an Implementation whose Performance, as Assessed by a Performance Assessor, can be replicated, within an agreed level, by another Performance Assessor.
|The attribute of an Implementation that copes with data outside of the stated application scope with an estimated degree of confidence.
|The domain of applicability of an MPAI Application Standard
|An entrepreneur who offers an Implementation as a service (e.g., a recommendation service) to Users.
|A set of Technical Specification, Reference Software, Conformance Testing, Performance Assessment, and Technical Report of an MPAI application Standard.
|(Framework) the normative specification of the AIF.
(Application) the normative specification of the set of AIWs belonging to an application domain along with the AIMs required to Implement the AIWs that includes:
1. The formats of the Input/Output data of the AIWs implementing the AIWs.
2. The Connections of the AIMs of the AIW.
3. The formats of the Input/Output data of the AIMs belonging to the AIW.
|A laboratory accredited to Assess the Grade of Performance of Implementations.
|The protocol specifying how Components can access timing information
|The set of AIM Connections of an AIW.
|A particular instance of the Application domain target of an Application Standard.
|A user of an Implementation.
|The Component interfacing the user with an AIF through the Controller
|A revision or extension of a Standard or of one of its elements.
|A cybersecurity model primarily focused on data and service protection that assumes no implicit trust.