Abatement

Noun

 * 1) The act of abating, or the state of being abated; a lessening, diminution, or reduction; removal or putting an end to; as, the abatement of a nuisance is the suppression thereof.
 * 2) The amount abated; that which is taken away by way of reduction; deduction; decrease; a rebate or discount allowed.
 * 3)  A mark of dishonor on an escutcheon; any figure added to the coat of arms tending to lower the dignity or station of the bearer.
 * 4)  The entry of a stranger, without right, into a freehold after the death of the last possessor, before the heir or devisee.

Synonyms for Abatement
reduction, lessening, diminution, decrease, subsidence, moderation.

Antonyms for Abatement
increase, augmentation, enlargement.

Derived terms

 * defense in abatement
 * plea in abatement

Thesaurus
abridgment, agio, allayment, alleviation, allowance, analgesia, anesthesia, anesthetizing, appeasement, assuagement, attenuation, attrition, bank discount, blunting, breakage, calming, cash discount, chain discount, charge-off, concession, contraction, cut, dampening, damping, deadening, debilitation, decrease, decrement, decrescence, deduction, deflation, demulsion, depreciation, depression, devitalization, dilution, diminishment, diminution, discount, drawback, dulcification, dulling, dying, dying off, ease, easement, easing, effemination, enervation, enfeeblement, evisceration, exhaustion, extenuation, fade-out, falling-off, fatigue, hushing, inanition, kickback, languishment, leniency, lessening, letdown, letup, lightening, loosening, lowering, lulling, miniaturization, mitigation, modulation, mollification, numbing, pacification, palliation, penalty, penalty clause, percentage, premium, price reduction, price-cut, quietening, quieting, rebate, rebatement, reduction, refund, relaxation, relief, remedy, remission, rollback, sagging, salvage, salving, scaling down, setoff, simplicity, slackening, softening, soothing, subduement, subtraction, tare, tempering, thinning, time discount, trade discount, tranquilization, tret, underselling, weakening, write-off

Etymology
From abatement,  abattement.