Merriam-Webster Online Dictionary
addition (noun)1.
a part added (as to a building or residential section)
2.
the result of - adding increase
3.
the act or process of adding , especially the operation of combining numbers so as to obtain an equivalent simple quantity
4.
direct chemical combination of substances into a single product
Merriam-Webster Online Thesaurus
addition (noun)1.
a smaller structure added to a main building
SYNONIMS:
addition, extension, penthouseRELATED WORDS:
arm, ell, wing2.
something added (as by growth)
SYNONIMS:
accretion, accrual, addendum, addition, augmentation, boost, expansion, gain, increment, more, plus, proliferation, raise, rise, step-up, supplement, uptickRELATED WORDS:
accumulation, assemblage, collection, gathering; complement; accession, appendix, continuation, extension, uptrend, upturn; jump, run-up, spikeNEAR ANTONYMS:
deduction, subtraction3.
the act or process of becoming greater in number
SYNONIMS:
accumulating, accumulation, addition, increase, mushrooming, proliferationRELATED WORDS:
doubling, quadrupling, tripling; creep, growth, rise, spread; enlargement, escalation, expansion; amplification, distension ( distention), inflation; accretion, accrual, augmentation, cumulation; extension, lengthening; boost, gain, hike, increment, riseNEAR ANTONYMS:
abatement, compressing, compression, condensation, condensing, constricting, constriction, contracting, contraction, diminishing, diminishment, diminution, drop, drop-off, fall, falloff, lessening, lowering, reduction, shrinkage, shrinking; retrenching, retrenchment, shortening