batter (v.) Look up batter at
"strike repeatedly, beat violently and rapidly," early 14c., from Old French batre "to beat, strike" (11c., Modern French battre "to beat, to strike"), from Latin battuere "to beat, strike," an old word in Latin, but almost certainly borrowed from Gaulish, from PIE root *bhau- "to strike" (source also of Welsh bathu "beat;" Old English beadu "battle," beatan "to beat," bytl "hammer, mallet").

The word began to be widely used in reference to domestic abuse in 1962. Related: Battered; battering. Battering-ram is an ancient weapon (Latin aries), but the phrase is attested only from 1610s.
batter (n.1) Look up batter at
in cookery, "a mixture of ingredients (flour, eggs, milk) beaten together," late 14c., from Old French batteure "a beating," from Latin battuere "to beat, knock" (see batter (v.)).
batter (n.2) Look up batter at
"one who strikes or beats with a bat," 1773, agent noun from bat (v.2). Earlier noun was batsman (1756).