Voice

Voice is a characteristic of a verb that indicates whether its subject acts or is acted upon.

Passive voice indicates that the subject is acted upon and consists of a form of 'be' and a past participle. The grammatical subject is not the logical subject in a passive sentence. Instead it receives the action described by the verb:

The kite was flown by a young girl.

Active voice indicates that the subject of the sentence acts. In Active voice the grammatical subject is the logical subject:

Bill swung the bat.