What is a copular verb?

A copular verb (aka linking verb) is a verb that’s used to connect the subject of a sentence with a subject complement.

A subject complement is a word or phrase (often a noun or adjective) that describes or names the subject. In other words, linking verbs help to indicate who or what someone or something is rather than what they do.

Some common linking verbs are “be,” “seem”, “become,” and “feel.” They can be used in sentences like “The dog seems upset” and “My great-grandmother was a journalist.”