A verb is a word that expresses an occurrence, act, or mode of being. Finite verbs, sometimes called main verbs, are limited by time (see tense), person, and number.
The finite verbs are highlighted in the following sentences:
The bear caught a salmon in the stream.
Who ate the pie?
A nonfinite verb form - such as a participle, infinitive, or gerund - is not limited by by time.