To give advantage to; to support; to advance the interest of.
From Middle English better, bettre, betre, from Old English betera ("better"), from Proto-Germanic *batizô ("better"), from Proto-Indo-European, from *bʰed-. Cognate with Sanskrit भद्र ("blessed, fortunate, happy, good"). For Germanic cognates: see *batizô. Related to best and battle. Compare also Icelandic batna ("to improve"), bót, German besser. More at batten, boot.