Thus, men in groups may be called a _crowd_, or a _mob_, a _committee_, or a _council_, or a _congress_, etc.
These are called COLLECTIVE NOUNS. They properly belong under common nouns, because each group is considered as a unit, and the name applied to it belongs to any group of its class.
[Sidenote: _Names for things thought of in mass._]
6. The definition given for common nouns applies more strictly to class nouns. It may, however, be correctly used for another group of nouns detailed below; for they are common nouns in the sense that the names apply to _every particle of similar substance_, instead of to each individual or separate object.
They are called MATERIAL NOUNS. Such are _glass_, _iron_, _clay_, _frost_, _rain_, _snow_, _wheat_, _wine_, _tea_, _sugar_, etc.
They may be placed in groups as follows:--
(1) The metals: _iron_, _gold_, _platinum_, etc.
(2) Products spoken of in bulk: _tea_, _sugar_, _rice_, _wheat_, etc.
(3) Geological bodies: _mud_, _sand_, _granite_, _rock_, _stone_, etc.
(4) Natural phenomena: _rain_, _dew_, _cloud_, _frost_, _mist_, etc.
(5) Various manufactures: _cloth_ (and the different kinds of cloth), _potash_, _soap_, _rubber_, _paint_, _celluloid_, etc.
7. NOTE.--There are some nouns, such as _sun_, _moon_, _earth_, which seem to be the names of particular individual objects, but which are not called proper names.
[Sidenote: _Words naturally of limited application not proper._]
The reason is, that in proper names the intention is _to exclude_ all other individuals of the same class, and fasten a special name to the object considered, as in calling a city _Cincinnati_; but in the words _sun_, _earth_, etc., there is no such intention. If several bodies like the center of our solar system are known, they also are called _suns_ by a natural extension of the term: so with the words _earth_, _world_, etc. They remain common class names.
[Sidenote: _Names of ideas, not things._]
8. Abstract nouns are names of qualities, conditions, or actions, considered abstractly, or apart from their natural connection.
When we speak of a _wise man_, we recognize in him an attribute or quality. If we wish to think simply of that quality without describing the person, we speak of the _wisdom_ of the man. The quality is still there as much as before, but it is taken merely as a name. So _poverty_ would express the condition of a poor person; _proof_ means the act of proving, or that which shows a thing has been proved; and so on.