The house was unexpectedly invaded by a gang of robbers'. What type of noun is 'gang'?

• 'The house was unexpectedly invaded by a gang of robbers'. Here 'gang' is a Collective noun.

• Collective Noun:
A Collective Noun is the name of a number (or collection) of persons or things taken together and spoken of as one whole.
Ex:
Crowd, mob, team, flock, herd, army, fleet, jury, family, national parliament committee, etc.
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• Gang শব্দের অর্থ দল, যেটা দিয়ে সমষ্টি বুঝায়,
- তাই এটা Collective Noun.

• A few things to be noted:
A fleet = a collection of ships or vessels.
An army = a collection of soldiers.
A crowd = a collection of people.
- All of these are used as Collective Nouns.

Source: High School English Grammar and Composition BY Wren and Martin.