Is it ensure, insure, or assure?
late 14c., from Old French chevron "rafter; chevron" (13c.), the accent mark so called because it looks like rafters of a shallow roof, from Vulgar Latin *caprione, from Latin caper "goat" (see cab); the hypothetical connection between goats and rafters being the animal's angular hind legs. Cf. Latin capreolus "props, stays, short pieces of timber for support," lit. "wild goat, chamoix."