_The boy shouts. The boys shout_. I have changed the form of the subject
_boy_ by adding an _s_ to it. The meaning has changed. _Boy_ denotes _one_
lad; _boys_, _two or more_ lads. This change in the form and meaning of
nouns is called +Number+. The word _boy_, denoting one thing, is in the
+Singular Number;+ and _boys_, denoting more than one thing, is in the
+Plural Number+.

Let the teacher write other nouns on the board, and require the pupils to
form the plural of them.


DEFINITIONS.

+_Modifications of the Parts of Speech_ are changes in their form, meaning,
and use+.

NUMBER.

+_Number_ is that modification of a noun or pronoun which denotes one thing
or more than one+.

+The _Singular Number_ denotes one thing+.

+The _Plural Number_ denotes more than one thing+.

+RULE.--The _plural_ of nouns is regularly formed by adding _s_ to the
singular+.