early 14c., "open to view," from Old French overt (Modern French ouvert), past participle of ovrir "to open," from Latin aperire "to open, uncover," from PIE *ap-wer-yo- from *ap- "off, away" + base *wer- "to cover" (see weir). Cf. Latin operire "to cover," from the same root with PIE prefix *op- "over;" and Lithuanian atveriu "open," uzveriu "shut."