1.  quantity(n = noun.tops) amount, measure - how much there is or how many there are of something that you can quantify;
is a kind of abstract entity, abstraction
has particulars: chance, probability, quantum, economic value, value, fundamental measure, fundamental quantity, definite quantity, indefinite quantity, relative quantity, metric, system of measurement, cordage, octane number, octane rating, magnetisation, magnetization, radical, volume, volume, proof, time unit, unit of time, point, point in time, period of play, play, playing period, interval, time interval

2.  quantity(n = noun.attribute) - an adequate or large amount; "he had a quantity of ammunition"
is a kind of amount
has particulars: abundance, copiousness, teemingness

3.  quantity(n = noun.cognition) - the concept that something has a magnitude and can be represented in mathematical expressions by a constant or a variable;
is a kind of concept, conception, construct
has particulars: quantum, term, numerical quantity, operand, variable, variable quantity, constant, constant quantity, invariable, parameter, mathematical product, product, amount, sum, total, proportional, binomial
Derived form verb quantify₂

1.  The attribute of being so much, and not more or less; the property of being measurable, or capable of increase and decrease, multiplication and division; greatness; and more concretely, that which answers the question “How much?”; measure in regard to bulk or amount; determinate or comparative dimensions; measure; amount; bulk; extent; size. [1913 Webster]

2.  That which can be increased, diminished, or measured; especially (Math.), anything to which mathematical processes are applicable. [1913 Webster]
" Quantity is discrete when it is applied to separate objects, as in number; continuous, when the parts are connected, either in succession, as in time, motion, etc., or in extension, as by the dimensions of space, viz., length, breadth, and thickness." [1913 Webster]

3.  A determinate or estimated amount; a sum or bulk; a certain portion or part; sometimes, a considerable amount; a large portion, bulk, or sum; as, a medicine taken in quantities, that is, in large quantities. [1913 Webster]
"The quantity of extensive and curious information which he had picked up during many months of desultory, but not unprofitable, study." [1913 Webster]

quantity, n. (pl. -ies)
1 the property of things that is measurable.
2 the size or extent or weight or amount or number.
3 a specified or considerable portion or number or amount (buys in quantity; the quantity of heat in a body).
4 (in pl.) large amounts or numbers; an abundance (quantities of food; is found in quantities on the shore).
5 the length or shortness of vowel sounds or syllables.
6 Math. a a value, component, etc. that may be expressed in numbers. b the figure or symbol representing this.

Idiom:
quantity mark a mark put over a vowel etc. to indicate its length. quantity surveyor a person who measures and prices building work. quantity theory the hypothesis that prices correspond to changes in the monetary supply.

Etymology:
ME f. OF quantit{eacute} f. L quantitas -tatis f. quantus how much

N  quantity, magnitude, size, amplitude, magnitude, mass, amount, sum, quantum, measure, substance, strength, force, mathematics, mathesis, category, general conception, universal predicament, armful, handful, mouthful, spoonful, capful, stock, batch, lot, dose, yaffle, quantitative, some, any, aught, more or less, a few, to the tune of, all of, a full, the sum of, fully, exactly, precisely.

N  greatness, magnitude, size, multitude, immensity, enormity, infinity, might, strength, intensity, fullness, importance, great quantity, quantity, deal, power, sight, pot, volume, world, mass, heap, stock, peck, bushel, load, cargo, cartload, wagonload, shipload, flood, spring tide, abundance, principal part, chief part, main part, greater part, major part, best part, essential part, bulk, mass, great, greater, large, considerable, fair, above par, big, huge, Herculean, cyclopean, ample, abundant, full, intense, strong, sound, passing, heavy, plenary, deep, high, signal, at its height, in the zenith, world-wide, widespread, far-famed, extensive, wholesale, many, goodly, noble, precious, mighty, sad, grave, heavy, serious, far gone, arrant, downright, utter, uttermost, crass, gross, arch, profound, intense, consummate, rank, uninitiated, red-hot, desperate, glaring, flagrant, stark staring, thorough-paced, thoroughgoing, roaring, thumping, extraordinary, important, unsurpassed, complete, august, grand, dignified, sublime, majestic, vast, immense, enormous, extreme, inordinate, excessive, extravagant, exorbitant, outrageous, preposterous, unconscionable, swinging, monstrous, overgrown, towering, stupendous, prodigious, astonishing, incredible, marvelous, unlimited, unapproachable, unutterable, indescribable, ineffable, unspeakable, inexpressible, beyond expression, fabulous, undiminished, unabated, unreduced, unrestricted, absolute, positive, stark, decided, unequivocal, essential, perfect, finished, remarkable, of mark, marked, pointed, veriest, noteworthy, renowned, truly, decidedly, unequivocally, purely, absolutely, seriously, essentially, fundamentally, radically, downright, in all conscience, for the most part, in the main, entirely, abundantly, widely, far and wide, greatly, much, muckle, well, indeed, very, very much, a deal, no end of, most, not a little, pretty, pretty well, enough, in a great measure, richly, to a large extent, to a great extent, to a gigantic extent, on a large scale, so, never so, ever so, ever so dole, scrap, shred, tag, splinter, rag, much, by wholesale, mighty, powerfully, with a witness, ultra, in the extreme, extremely, exceedingly, intensely, exquisitely, acutely, indefinitely, immeasurably, beyond compare, beyond comparison, beyond measure, beyond all bounds, incalculably, infinitely, preeminently, superlatively, immoderately, monstrously, preposterously, inordinately, exorbitantly, excessively, enormously, out of all proportion, with a vengeance, particularly, remarkably, singularly, curiously, uncommonly, unusually, peculiarly, notably, signally, strikingly, pointedly, mainly, chiefly, famously, egregiously, prominently, glaringly, emphatically, kat exochin, strangely, wonderfully, amazingly, surprisingly, astonishingly, incredibly, marvelously, awfully, stupendously, peculiarly, furiously, severely, desperately, tremendously, extravagantly, confoundedly, deucedly, devilishly, with a vengeance, a outrance, a toute outrance, painfully, sadly, grossly, sorely, bitterly, piteously, grievously, miserably, cruelly, woefully, lamentably, shockingly, frightfully, dreadfully, fearfully, terribly, horribly, a maximis ad minima, greatness knows itself, mightiest powers by deepest calms are fed, minimum decet libere cui multum licet, some are born great, some achieve greatness, and some have greatness thrust upon them.

N  assemblage, collection, collocation, colligation, compilation, levy, gathering, ingathering, muster, attroupement, team, concourse, conflux, congregation, contesseration, convergence, meeting, levee, reunion, drawing room, at home, conversazione, assembly, congress, convention, conventicle, gemote, conclave, posse, posse comitatus, Noah's ark, miscellany, collectanea, museum, menagerie, museology, crowd, throng, group, flood, rush, deluge, rabble, mob, press, crush, cohue, horde, body, tribe, crew, gang, knot, squad, band, party, swarm, shoal, school, covey, flock, herd, drove, atajo, bunch, drive, force, mulada, remuda, roundup, array, bevy, galaxy, corps, company, troop, troupe, task force, army, regiment, host, populousness, clan, brotherhood, fraternity, sorority, association, volley, shower, storm, cloud, group, cluster, Pleiades, clump, pencil, set, batch, lot, pack, budget, assortment, bunch, parcel, packet, package, bundle, fascine, fasces, bale, seron, seroon, fagot, wisp, truss, tuft, shock, rick, fardel, stack, sheaf, haycock, fascicle, fascicule, fasciculus, gavel, hattock, stook, accumulation, congeries, heap, lump, pile, rouleau, tissue, mass, pyramid, bing, drift, snowball, snowdrift, acervation, cumulation, glomeration, agglomeration, conglobation, conglomeration, conglomerate, coacervate, coacervation, coagmentation, aggregation, concentration, congestion, omnium gaterum, spicilegium, black hole of Calcutta, quantity, collector, gatherer, whip, whipper in, assembled, closely packed, dense, serried, crowded to suffocation, teeming, swarming, populous, as thick as hops, all of a heap, fasciculated cumulative, the plot thickens, acervatim, tibi seris tibi metis.

complex quantity, constant quantity, definite quantity, fundamental quantity, indefinite quantity, large indefinite quantity, numerical quantity, parametric quantity, prime quantity, quantity unit, relative quantity, small indefinite quantity, unknown quantity, variable quantity