# PhysicsEvents.WorldDefinitionChangeEventHandler

> Event handler for a world definition change event callback.

## Definition

* **Type:** Delegate
* **Namespace:** [Unity.U2D.Physics](/engine/6000.5/script-reference/unity/u2d/physics.md)
* **Assembly:** UnityEngine.PhysicsCore2DModule

```csharp
public delegate void PhysicsEvents.WorldDefinitionChangeEventHandler(PhysicsWorld world)
```