docs: add glossary for openedx-events ecosystem

docs/reference/glossary.rst

@@ -0,0 +1,47 @@
+Open edX Events Glossary
+##########################
+
+This glossary provides definitions for some of the terms to ease the adoption
+of the Open edX Events library.
+
+Event Receiver
+--------------
+
+An event receiver, handler or listener is a function that listens for a specific
+event and executes custom logic in response to the event being triggered. Since
+Events are Django-signals, then receivers are registered with the signal
+dispatcher and are called when the event is emitted. In Django, event receivers
+are known as signal handlers. Both terms are used interchangeably.
+
+Event Trigger
+-------------
+
+An event trigger is the action that causes an event to be emitted. When a
+trigger action occurs, the associated event is emitted, and any registered event
+receivers are called to handle the event.
+
+Event Payload
+-------------
+
+The event payload is the data associated with an event that is passed to event
+receivers when it's triggered. The payload of an event are data attribute classes (e.g. `CourseEnrollmentData`, `UserData`, etc.)
+that carry data about the event such as the event name, timestamp, and any additional
+metadata and information about the actual event. For more information, see the
+`ADR: Events Payload`_.
+
+Event Type
+----------
+
+The event type is a unique identifier for an event that distinguishes it from
+other events. For example, `org.openedx.content_authoring.xblock.published.v1`. The event type is used to
+identify the event, its purpose, and version. In the event-bus context, the event
+type is used to connect events to the appropriate topics in the ``EVENT_BUS_PRODUCER_CONFIG``.
+
+Event Definition
+----------------
+
+An event definition is the instantiation of the `OpenEdxPublicSignal` class that
+defines the structure and metadata of an event. The event definition includes
+information such as the event name, description, payload, and version. Event
+definitions are used to create events which are later imported into the
+application and used to trigger events using the `send_event` method.

docs/reference/index.rst

@@ -6,5 +6,6 @@ References
    :caption: Contents:
 
    events
+   glossary
    oeps
    architecture-subdomains