Cinch, derived from the Spanish word cincha
"), came to mean a firm hold or a tight grip because of the physical
object used in securing a horse saddle. It then became an American idiom
for something sure
...it's a cinch!
Cinch is also used as a verb, both meaning "to fix a saddle securely" and in more widespread usage, "to make secure; to tighten" (for example, if I were to "cinch my belt" I'd be a happy camper because it probably meant I lost weight and could now tighten my belt further *grin*). thanks, anotherone