Is flock a collective noun and common in grammar?

Yes, "flock" is a collective noun. It refers to a group of birds, typically of the same species.

Collective nouns are words that refer to a group of individuals considered as a single unit. Other examples of collective nouns include:

* Team (group of people)

* Family (group of related people)

* Jury (group of people)

* Committee (group of people)

* Army (group of soldiers)

Common in grammar?

Yes, "flock" is a common collective noun, particularly when talking about birds. It's frequently used in both spoken and written English.

However, it's worth noting that while "flock" is usually associated with birds, it can also be used for other groups, like a flock of sheep or a flock of tourists.