sphincter
noun /ˈsfɪŋktə(r)/
/ˈsfɪŋktər/
(anatomy- a ring of muscle that surrounds an opening in the body and can become tight to close it
括约肌 - the anal sphincter
肛门括约肌
词源late 16th cent.: via Latin from Greek sphinktēr, from sphingein ‘bind tight’. - the anal sphincter