[sfingk-ter] 
| a circular band of voluntary or involuntary muscle that encircles an orifice of the body or one of its hollow organs. |
r, equiv. to sphing-, base of sphíngein to hold tight + -tēr suffix denoting agent
[sfingk-teer-ee-uhl] , sphinc⋅ter⋅ic [sfingk-ter-ik] , sphinc⋅ter⋅ate [sfingk-ter-it, -tuh-reyt] , adjective | sphinc·ter (sfĭngk'tər) n. A ringlike muscle that normally maintains constriction of a body passage or orifice and that relaxes as required by normal physiological functioning. [Late Latin sphinctēr, from Greek sphinktēr, from sphingein, to bind tight.] sphinc'ter·al adj. |
sphincter sphinc·ter (sfĭngk'tər)
n.
A ringlike muscle that normally maintains constriction of a body passage or orifice and that relaxes as required by normal physiological functioning. Also called anatomical sphincter.