Well, with all due respect to the ferociousness of your grammar guarding...er...reptile:
the link
A collective noun is a noun that denotes a collection of persons or things regarded as a unit.
Usage Note: In American usage, a collective noun takes a singular verb when it refers to the collection considered as a whole, as in:
* The family was united on this question.
* The enemy is suing for peace.
It takes a plural verb when it refers to the members of the group considered as individuals, as in:
* My family are always fighting among themselves.
* The enemy were showing up in groups of three or four to turn in their weapons.
In British usage, however, collective nouns are more often treated as plurals:
* The government have not announced a new policy.
* The team are playing in the test matches next week.
A collective noun should not be treated as both singular and plural in the same construction; thus:
* The family is determined to press its (not their) claim.
Among the common collective nouns are:
* committee
* clergy
* company
* enemy
* group
* family
* flock
* public
* team
Of course, this is a British definition, and what do they know about English, eh?
