The Collaborative International Dictionary
Fraenum
Fraenum \Fr[ae]"num\, or Frenum \Fre"num\, n.; pl. E. Fr[ae]nums, L. Fr[ae]na. [L., a bridle.] (Anat.) A connecting fold of membrane serving to support or restrain any part; as, the fr[ae]num of the tongue.
Wiktionary
fraenum
n. (alternative form of frenum English)