The term collective noun denotes a group of objects, people, animals, or ideas as a single concept, or a single thing. Common examples of collective noun include: army, band, cast, committee, crowd, family, faculty, group, jury, society, school, staff, team, and troop.
You cannot have a committee, team, or family of one; you need at least two people to compose the unit. Because people behave as both herd animals and solitary creatures, collective nouns can be either singular or plural, depending on context.