What is collective noun for trash or garbage?

There isn't a widely accepted collective noun specifically for trash or garbage. However, you can use some creative options based on the context:

General terms:

* Heap of trash/garbage

* Pile of trash/garbage

* Mound of trash/garbage

* Dump of trash/garbage

* Collection of trash/garbage

More specific terms:

* Litter (for small bits of trash)

* Debris (for broken or scattered items)

* Refuse (formal term for garbage)

* Waste (general term for unusable materials)

Figurative language:

* A sea of trash

* A mountain of garbage

The best choice will depend on the specific situation and the tone you want to convey.