For all practical purposes, the foregoing definition and division of the
verb, though, perhaps, not philosophically correct, will be found as
_convenient_ as any other. I adopt them, therefore, to be consistent
with the principle, that, in arranging the materials of this treatise, I
shall not alter or reject any established definition, rule, or principle
of grammar, unless, in my humble judgment, some _practical advantage_ to
the learner is thereby gained. The following, some consider a good
definition.

A VERB is a word which _expresses affirmation_.

An _active verb_ expresses action; and

The _nominative case_ is the actor, or subject of the verb; as, _John
writes_.

In this example, which is the _verb?_ You know it is the word _writes_,
because this word signifies to _do;_ that is, it expresses _action_,
therefore, according to the definition, it is an _active verb_. And you
know, too, that the noun _John_ is the _actor_, therefore John is in the
_nominative case_ to the verb writes. In the expressions, The man
walks--The boy plays--Thunders roll--- Warriors fight--you perceive that
the words _walks, plays, roll_, and _fight_, are _active verbs;_ and you
cannot be at a loss to know, that the nouns _man, boy, thunders_, and
_warriors_, are in the _nominative case._

As no _action_ can be produced without some agent or moving cause, it
follows, that every active verb must have some _actor_ or _agent_. This
_actor, doer_, or _producer of the action_, is the nominative.