Identify the collective noun in the following sentence.

The flock of geese was startled and took off into flight when they heard the loud noise.

A collective noun is conveniently used to represent a certain noun into a group. They are very specific to the noun used. Hence, it is important for language syntax and for sophistication. Take 'den of lions' for example. A group of lions could be collectively referred to as den.

In this problem, the collective noun is 'flock' which refers to a group of geese.