What is the meaning of Constrictor?

That which constricts or tightens:

  1. A muscle whose contraction narrows a vessel or passage or compresses an organ.

    A muscle whose contraction narrows a vessel or passage or compresses an organ.

    Each of the muscles which constrict the pharynx; ellipsis of pharyngeal constrictor..

    Ellipsis of boa constrictor.: a python or similar snake that kills by constriction.

    That which constricts; constrictor.

    constrictor

    constricting

    Source: wiktionary.org