Grammatical voice

Grammatical voice is the relationship between verbs and the noun phrases which function as their grammatical subjects.

Grammarians generally recognise two voices in English, the active, in which the grammatical subject is the agent and performs the action denoted by the verb, as in John opened the door; and the Passive, in which the grammatical subject is the patient that is affected by the action of the verb, as in The door was opened (by John).

Only transitive verb and ambitransitive verbs have passive forms as they can be used transitively.

There are a number of verbs used intransitively with a meaning in which the grammatical subject is not the performer of the action as such - the door opened. Some grammarians refer to these verbs as being in the middle voice, i.e. halfway between active and passive. Most grammarians, however, consider that such verbs (known as ergative verbs) are functioning in the active voice.