From Second Life Wiki
A coalesced (or grouped) object contains multiple objects which appear as one entry in a resident's inventory, marked with the sign. This can happen either via auto-return or when multiple objects are selected and taken at once. Coalesced objects can not be attached to an avatar.
- What are coalesced objects?
- Linden trees in coalesced objects
- Don't rez coalesced objects close to no-build parcels