Noun
a noun that is singular in form but refers to a group of people or things
Source: WordNetCollective nouns main A collective noun is a word that designates a group of objects or beings regarded as a whole, such as "flock", "team", or "corporation". Source: Internet
Formally, collective noun forms such as “a group of people” are represented by second-order variables, or by first-order variables standing for sets (which are well-defined objects in mathematics and logic). Source: Internet