1.be (a part) of a whole. "single parents constitute a great proportion of the poor" synonyms: amount to, add up to, account for, form, make up, compose, comprise, represent "farmers constituted 10 percent of the population" 2. give legal or constitutional form to (an institution); establish by law. synonyms: inaugurate, initiate, establish, found, create, set up, put in place, start, begin, originate, form, organize, develop, shape; More