From Minetest

Objects (or entities) are things in Minetest which are able to move in the world freely. They do not have to fit into a grid like nodes, anything that exists in the world that is not in the node grid (e.g. players, mobs, vehicles) are implemented as objects.

Each object behaves differently. Some objects do collide with nodes and/or other objects, while some don't. Objects may have health and can be attacked and destroyed by inflicting damage on them.

Engine provided objects

Falling Node.png Falling Block Item entity.png Item stack Unknown Object.png Unknown Object