Change:
ekr had the following comment: S 2.4. Why do you have two terminology sections? I would merge them.
Most of my comments are consequential.

Discussion:
invoked.  Both subject to constraints of the implementation, of course. <del> For the purpose of this document, we define the following terminology to talk about WebRTC things: </del> <ins> The following terms are used across the documents specifying the WebRTC suite, in the specific meanings given here.  Not all terms are used in this document.  Other terms are used in their commonly used meaning. </ins> <del> A WebRTC browser (also called a WebRTC User Agent or WebRTC UA) is something that conforms to both the protocol specification and the Javascript API cited above. </del> <ins> Undefined term.  See "SDP Agent" and "ICE Agent". </ins> <del> A WebRTC non-browser is something that conforms to the protocol specification, but does not claim to implement the Javascript API. This can also be called a "WebRTC device" or "WebRTC native application". </del> <ins> A specification of a set of calls and events, usually tied to a programming language or an abstract formal specification such as WebIDL, with its defined semantics. </ins> <del> A WebRTC endpoint is either a WebRTC browser or a WebRTC non- browser.  It conforms to the protocol specification. </del> <ins> Used synonymously with "Interactive User Agent" as defined in the HTML specification W3C.WD-html5-20110525.  See also "WebRTC User Agent". </ins> <del> A WebRTC-compatible endpoint is an endpoint that is able to successfully communicate with a WebRTC endpoint, but may fail to meet some requirements of a WebRTC endpoint.  This may limit where in the network such an endpoint can be attached, or may limit the security guarantees that it offers to others.  It is not constrained by this specification; when it is mentioned at all, it is to note the implications on WebRTC-compatible endpoints of the requirements placed on WebRTC endpoints. </del> <ins> An abstraction that allows data to be sent between WebRTC endpoints in the form of messages.  Two endpoints can have multiple data channels between them. </ins> <del> A WebRTC gateway is a WebRTC-compatible endpoint that mediates media traffic to non-WebRTC entities. </del> <ins> An implementation of the Interactive Connectivity Establishment (ICE) I-D.ietf-ice-rfc5245bis protocol.  An ICE Agent may also be an SDP Agent, but there exist ICE Agents that do not use SDP (for instance those that use Jingle XEP-0166). Communication between multiple parties, where the expectation is that an action from one party can cause a reaction by another party, and the reaction can be observed by the first party, with the total time required for the action/reaction/observation is on the order of no more than hundreds of milliseconds. Audio and video content.  Not to be confused with "transmission media" such as wires. The path that media data follows from one WebRTC endpoint to another. A specification of a set of data units, their representation, and rules for their transmission, with their defined semantics.  A protocol is usually thought of as going between systems. Media where generation of content and display of content are intended to occur closely together in time (on the order of no more than hundreds of milliseconds).  Real-time media can be used to support interactive communication. The protocol implementation involved in the Session Description Protocol (SDP) offer/answer exchange, as defined in RFC3264 section 3. Communication that happens in order to establish, manage and control media paths and data paths. The communication channels used between entities participating in signaling to transfer signaling.  There may be more entities in the signaling path than in the media path. (also called a WebRTC User Agent or WebRTC UA) Something that conforms to both the protocol specification and the Javascript API cited above. Something that conforms to the protocol specification, but does not claim to implement the Javascript API.  This can also be called a "WebRTC device" or "WebRTC native application". Either a WebRTC browser or a WebRTC non-browser.  It conforms to the protocol specification. An endpoint that is able to successfully communicate with a WebRTC endpoint, but may fail to meet some requirements of a WebRTC endpoint.  This may limit where in the network such an endpoint can be attached, or may limit the security guarantees that it offers to others.  It is not constrained by this specification; when it is mentioned at all, it is to note the implications on WebRTC-compatible endpoints of the requirements placed on WebRTC endpoints. A WebRTC-compatible endpoint that mediates media traffic to non- WebRTC entities. </ins> All WebRTC browsers are WebRTC endpoints, so any requirement on a WebRTC endpoint also applies to a WebRTC browser.

"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC2119. <del> The following terms are used across the documents specifying the WebRTC suite, in the specific meanings given here.  Not all terms are used in this document.  Other terms are used in their commonly used meaning. The list is in alphabetical order. Undefined term.  See "SDP Agent" and "ICE Agent". Application Programming Interface - a specification of a set of calls and events, usually tied to a programming language or an abstract formal specification such as WebIDL, with its defined semantics. Used synonymously with "Interactive User Agent" as defined in the HTML specification W3C.WD-html5-20110525.  See also "WebRTC User Agent". An abstraction that allows data to be sent between WebRTC endpoints in the form of messages.  Two endpoints can have multiple data channels between them. An implementation of the Interactive Connectivity Establishment (ICE) I-D.ietf-ice-rfc5245bis protocol.  An ICE Agent may also be an SDP Agent, but there exist ICE Agents that do not use SDP (for instance those that use Jingle XEP-0166). Communication between multiple parties, where the expectation is that an action from one party can cause a reaction by another party, and the reaction can be observed by the first party, with the total time required for the action/reaction/observation is on the order of no more than hundreds of milliseconds. Audio and video content.  Not to be confused with "transmission media" such as wires. The path that media data follows from one WebRTC endpoint to another. A specification of a set of data units, their representation, and rules for their transmission, with their defined semantics.  A protocol is usually thought of as going between systems. Media where generation of content and display of content are intended to occur closely together in time (on the order of no more than hundreds of milliseconds).  Real-time media can be used to support interactive communication. The protocol implementation involved in the Session Description Protocol (SDP) offer/answer exchange, as defined in RFC3264 section 3. Communication that happens in order to establish, manage and control media paths and data paths. The communication channels used between entities participating in signaling to transfer signaling.  There may be more entities in the signaling path than in the media path. </del> 3. For browser-based applications, the model for real-time support does