A verb that is joined with a helping verb is called?

A verb that is joined with a helping verb is referred to as a compound verb. This term applies when a main verb is combined with one or more auxiliary (or helping) verbs to convey a more complex tense, mood, or voice. For instance, in the phrase "is running," "is" serves as the helping verb, and together with "running," they create a compound verb that describes an ongoing action.

In contrast, terms like simple verb, complex verb, and transitive verb each have distinct meanings. A simple verb typically refers to a single verb without any auxiliary components, while a complex verb is not a standard grammatical term commonly used in the same way. Transitive verbs are specific to the action they perform, requiring a direct object to complete their meaning, which doesn't necessarily relate to the use of helping verbs. Thus, the definition of a compound verb aligns perfectly with the concept of adding helping verbs to main verbs for a fuller expression of action.