What are events and event producers/consumers in the context of EDA?

An event is anything that happens in a business environment or their customers’ ecosystem.
The applications and services that trigger events are called event producers. Producers know when certain events occur and publish them to show that they happened while including the relevant information.

The event hub receives the notifications sent out by producers and notify other parties that have registered their interest in receiving certain events. Those interested parties are called event consumers. They can be organised in consumer groups by the type of events they are interested in.