valency

valency (valens): a feature of verbs. The valency of a verb determines how many other clause elements there must be in a sentence. A verb with a valency of one (=a one-place verb) needs only a subject in order to build a complete sentence. A verb with a valency of two (=a two-place verb) needs two other clause elements (subject + direct object , subject + subject predicative, or subject + adverbial).A verb with a valency of three (=a three-place verb) needs three other clause elements (subject+ indirect object + direct object, subject+ direct object + object predicative, or subject + direct object + adverbial). No English verb has a valency of more than three.