overhand (adv.)youdaoicibaDictYouDict[overhand 词源字典]
1570s, "upside down," from over- + hand. Sense in tennis, etc., in reference to hand position above that which is gripped, is first recorded 1861. As an adjective, of throws, strokes, or bowls, "done with the hand raised above the shoulder," it is first recorded 1828 (in cricket).[overhand etymology, overhand origin, 英语词源]