Rebate
late Middle English (as a verb in the sense ‘diminish (a sum or amount)’): from Anglo-Norman French rebatre ‘beat back’, also ‘deduct’.
wiktionary
From Old French rabatre < batre. See also abate.
etymonline
rebate (v.)
late 14c., rebaten, "to reduce, diminish;" early 15c., "to deduct, subtract," from Old French rebatre, rabatre, rabattre "beat down, drive back," also "deduct," from re-, "back," or perhaps "repeatedly" (see re-) + abattre "beat down" (see abate).
Original senses now are obsolete. The meaning "to pay back (a sum) as a rebate" is from 1957 and might be from rebate (v.). Related: Rebated; rebating.
rebate (n.)
1650s, "an allowance by way of discount, deduction from a sum of money to be paid," from rebate (v.). By 1882 as "a repayment, money paid back."
