COPULA. A VERB that joins a SUBJECT to its COMPLEMENT. A term in the GRAMMAR of English for the verb be, but often extended to other verbs with a similar function. These copular verbs (also linking verbs) can be divided semantically into two types: (1) Those like be that refer to a current state: appear, feel, remain, seem, sound. (2) Those that indicate a result of some kind: become, get (wet); go (bad); grow (old); turn (nasty). Be is the copula that most often takes adverbial complements: Maud was in the garden; Dinner is at seven. All others take subject complements which characterize or identify the subject: I felt cold; I felt a fool.

copula (gram.) part of a proposition connecting subject and predicate, spec. the verb ‘to be’; connection XVII. — L. cōpula connection, linking of words, f. CO- + apere fasten; see APT, -ULE, and cf. COUPLE.
So copulate †couple; unite sexually. XVII. f. pp. stem of L. cōpulāre, f. cōpula; see -ATE 3. copulation XIV. — (O)F. — L.

cop·u·la / ˈkäpyələ/ • n. Logic & Gram. a connecting word, in particular a form of the verb be connecting a subject and complement.DERIVATIVES: cop·u·lar / ˈkäpyələr/ adj.