A collective noun is a noun naming a group of things, animals, or persons. You could count the individual members of the group, but you usually think of the group as a whole is generally as one unit. You need to be able to recognise collective nouns in order to maintain subject-verb agreement. A collective noun is similar to a non-countable noun, and is roughly the opposite of a countable noun. 

In each of the following sentences, the highlighted word is a collective noun (observe how the verb is conjugated in italics):

• • The flock of geese spends most of its time in the pasture.  (The collective noun "flock" takes the singular verb "spends.")

  • The jury is dining on take-out chicken tonight.  (In this example the collective noun "jury" is the subject of the singular compound verb "is dining.")

  • The steering committee meets every Wednesday afternoon.  (Here the collective noun "committee" takes a singular verb, "meets.")

  • The class was startled by the bursting light bulb.  (In this sentence the word "class" is a collective noun and takes the singular compound verb "was startled.")

Table: little known collective nouns

Like idiomatic expressions, some collective nouns will seem funny or strange to second language learners. Other collective nouns are well known, such as the word "group," as in "a group of people," or "a group of trees." Here is a a list of some, but not all, collective nouns: