jess

(jĕs)
n.
A short strap fastened around the leg of a hawk or other bird used in falconry, to which a leash may be fastened.

tr.v., jessed, jess·ing, jess·es.
To put jesses or a jess on (a hawk, for example).

[Middle English ges, from Old French, pl. of jet, something thrown, from Vulgar Latin *iectus, alteration of Latin iactus, past participle of iacere, to throw.]