The Collaborative International Dictionary
Fermillet
Fermillet \Fer"mil*let\, n. [OF., dim. of fermeil, fermail,
clasp, prob. fr. OF. & F. fermer to make fast, fr. ferme
fast. See Firm.]
A buckle or clasp. [Obs.]
--Donne.
Wiktionary
fermillet
n. (context obsolete English) A buckle or clasp.