# Glossary

This section defines terms used throughout the `aioxmpp` documentation.

Conversation
  A context for communication between two or more entities. It defines a transport medium (such as direct XMPP or a Multi-User-Chat), a set of members along with their addresses and possibly additional features such as archive access method.
Conversation Member
  Representation of an entity which takes part in a Conversation. The actual definition of “taking part in a conversation” depends on the specific medium used.
Tracking Service
  A Service which provides functionality for updating `aioxmpp.tracking.MessageTracker` objects.
Service
  A subclass of `aioxmpp.service.Service` which supplements the base `aioxmpp.Client` with additional functionality. Typically, a service implements a part of one or more XEPs.
Service Member

  A Conversation Member representing the service over which the conversation is run. For example, some XEP-0045 multi-user chat service implementations send messages to all occupants as a service user. Those messages appear in `aioxmpp.muc` as coming from the service member.

  Relevant entities:

  - `aioxmpp.im.conversation.AbstractConversation.service_member`

    > - `aioxmpp.muc.Room.service_member`

  - `aioxmpp.im.conversation.AbstractConversationMember`

    > - `aioxmpp.muc.ServiceMember`

XEP
XMPP Extension Proposal
  An XMPP Extension Proposal (or XEP) is a document which extends the basic RFCs of the XMPP protocol with additional functionality. Many important instant messaging features are specified in XEPs. The index of XEPs is located on xmpp.org.