---
schema_version: "1"
id: d8567665a115cdd13fb7b4961f87b488c66c31a5cda9b254683beb4b5d24d94b
title: Event Definition Overview
collection: developer
version: current
locale: en-us
portal_url: https://docs.salesforce.com/developer/current/en-us/marketing-cloud/guides/mc-apis/event-definition-key.md
canonical_url: https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/event-definition-key.html
source_site: developer.salesforce.com
content_type: documentation
content_hash: b80015e1a328ab7118314dd73430f992437262e124fb0e7b73efab4bd981bfe0
products:
  - Marketing Cloud Engagement APIs and Programmatic Languages
  - Marketing Cloud
---
# Event Definition Overview

Event definitions define the name and a data schema for an event. When an event definition is created, the API defines the event definition key. The API then uses the event definition key to route events to the appropriate journeys. For example, an event definition has the key "Acme-MovieRented". Two or more journeys should be invoked when a contact rents a movie. Use the same event definition key to invoke both journeys when a contact rents a movie.

The Journey Specification requires an event (`trigger`) object to have an event definition key set in order for the journey to be published.

## Example Event Object

```
{
    "key": "a-simple-journey",
    "name": "My Workflow",
    "description": "This is a description of my workflow.",
    "version": 1,
    "workflowApiVersion": 1.0,
    "triggers": [
        {
            "key": "move-rented-event-activity-key",
            "name": "Move Rented",
            "type": "Event",
            "arguments": [],
            "eventDefinitionKey": "Acme-MovieRented"
        }
    ]
}
```

## Related Items

- [POST /eventDefinition Resource](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/createEventDefinition.md)
- [List of All Event Definition Resources](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/jb-api-specification.md)
- [Fire an Entry Event](https://developer.salesforce.com/docs/marketing/marketing-cloud/guide/how-to-fire-an-event.md)