Word Study
sphincter
CIDE DICTIONARY
sphincter, n. [NL., fr. to bind tight.].
A muscle which surrounds, and by its contraction tends to close, a natural opening; as, the sphincter of the bladder. [1913 Webster]
sphincter, a.
Of, pertaining to, or designating, a sphincter; as, a sphincter muscle. [1913 Webster]
OXFORD DICTIONARY
sphincter, n. Anat. a ring of muscle surrounding and serving to guard or close an opening or tube, esp. the anus.
Derivative
sphincteral adj. sphinctered adj. sphincterial adj. sphincteric adj.
Etymology
L f. Gk sphigkter f. sphiggo bind tight
THESAURUS
sphincter
O, annular muscle, annulus, areola, aureole, chaplet, circle, circuit, circumference, circus, closed circle, corona, coronet, crown, cycle, diadem, discus, disk, eternal return, fairy ring, garland, glory, halo, lasso, logical circle, loop, looplet, magic circle, noose, orbit, radius, ring, rondelle, round, roundel, saucer, vicious circle, wheel, wreathFor further exploring for "sphincter" in Webster Dictionary Online