A verb is a word used to describe an action, state, or occurrence.
A verb is a word used to describe an action, state, or occurrence, and forming the main part of the predicate of a sentence, such as hear, become, and happen.
Verb forms sometimes vary depending on tense (help, helped), number (is, are), person (am, is), and mood (am, be). Verb phrases can also carry "aspect" ("I sing" uses the simple aspect; "I am singing" expresses the continuous or progressive aspect; "I have sung" expresses the perfect aspect).
Non-finite forms of the verb include the to-infinitive (to be), the bare infinitive (be), and the participles.
Main verbs can be distinguished from auxiliary verbs (which include modals such as must and can).