Collective nouns are countable nouns that refer to groups of people, objects, or things. A collective noun differs from a mass noun (a noun that cannot be counted—e.g., love, water, evidence) because it can be pluralized. For example, each of these collective nouns refers to a group but can itself be pluralized:
Singular vs. plural verbs
The consensus among English grammar and usage authorities is that collective nouns sometimes take singular verb forms (e.g., the team is) and sometimes plural verb forms (the team are). But there are no clear rules, and in many cases either approach would work.
When the noun is treated collectively and the individuals within the group aren’t important to the meaning of the sentence, singular verb forms work well—for example, the team is in last place; the staff is in the meeting room; the family has moved out. But plural verbs, at least in these examples, would not be considered incorrect.
When the meaning of the sentence requires that individuals within the group be differentiated, plural forms work better—for example, the team have various training regimens; the staff are unable to agree among themselves; my family live all over the country. These, however, might sound odd to some speakers of English. American-English speakers, in particular, tend to to treat collective nouns as singular in most cases. In each of these examples, an American writer might insert members after the collective noun.