ぐんしゅう群集gunshuu
1.

A gathering of individuals congregating in one location, often forming a significant number that creates a collective presence.

2.

An informal and temporary collective of people unified by shared interests or purposes, which may lead to behaviors outside of their usual social norms.

3.

A grouping of various species in the natural world that coexist and interact for ecological reasons.

4.

A classification unit in botany that describes a specific plant community based on the composition of species within it.

Example:

群集は嬉しさのあまり歓声を上げた。