collective noun
Definition - A singular noun that stands for a collection of things.

Example -

(1) a flock of seagulls
(2) a bunch of idiots
(3) a batch of cookies
(4) a group of Liberals

Oxford English Dictionary -
The term's first citation is from 1520:
"The nominatyue case of the nowne collectiue."
( Whitinton Vulg. (1527) 6)

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