n. That which constricts, contracts, or draws together; specifically, in anatomy, a muscle which draws parts together, or closes an opening; a sphincter: as, the constrictor of the esophagus.n. A large serpent which envelops and crushes its prey in its folds: as, the boa-constrictor. See boa.n. The technical specific name of the common black-snake of North America, Bascanion constrictor. See cut under black-snake.Acting as a constrictor; constricting: as, a constrictor muscle.