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

The editors of my dictionary have overlooked a couple anatomical entities of occasional importance
At the base of the tongue there is a membrane in the midline that in rare instances limits the
movements of the tongue. There is a similar structure that attaches the prepuce to the base of the
glans penis that also occasionally prevents proper retraction of the foreskin. Surgical kits used to
provide a cannula, with a special tip with an open ended slot that would fit around the frenulum, making
it possible to cut it without injuring the surfaces to which the frenulum was attached.