Most common nouns come under one of the classes defined below.

A Glass Noun is a name applied to each one of a class; for example, continent, girl, animal.

A Material Noun is a name applied to any quantity of stuff of the same kind; for example, cloth, salt.

An Abstract Noun is a name of an attribute; for example, bravery, weakness, exercise.

Exercise 168. Development

herd, swarm, flocks, group, jury, crowds, pair.

Are these nouns common or proper? Why? To what class of common nouns does each belong? Do you see any peculiarity of these nouns that most class nouns do not have? Such nouns are called collective nouns.