modal auxiliary

modal auxiliary (modalt hjelpeverb): see also auxiliary. An auxiliary that expresses modality (obligation, permission, possibility, ability; or degrees of probability). The modal auxiliaries proper are can/could, may/might, must, shall/should, will/would, ought to. These modals have no non-finite forms. There can only be one modal auxiliary proper in a verb phrase (although they can combine with marginal modal auxiliaries and auxiliary equivalents).