frenulum
noun/ˈfrenjələm/, /ˈfriːnjələm/
/ˈfrenjələm/
(British English also fraenulum
(anatomy)/ˈfriːnjələm/
)- a small fold of skin that prevents an organ from moving too much, for example the fold of skin under the tongue
系带 Word Originearly 18th cent.: modern Latin, diminutive of Latin frenum ‘bridle’.