frenulum
n.,
pl. 3lums or 3la 73l!8 5ModL, dim. of frenum: see fol.6
1 a small frenum
2 Zool. a stiff bristle or group of bristles extending from the hind wing of some moths and interlocking with a structure on the front wing, linking the wings together in flight

In human anatomy, the small fold under tongue in midline to floor of mouth. Also a fold attaching
prepuce to glans penis in ventral midline.