1.  magnitude(n = noun.attribute) - the property of relative size or extent (whether large or small); "they tried to predict the magnitude of the explosion"; "about the magnitude of a small pea"
is a kind of property
has particulars: absolute magnitude, dimension, proportion, order, order of magnitude, dimension, degree, amplitude, multiplicity, triplicity, size, size, bulk, mass, volume, muchness, intensity, intensity level, strength, amount, extent
Derived forms verb magnify₃, verb magnify₁

2.  magnitude(n = noun.linkdef) order of magnitude - a number assigned to the ratio of two quantities; two quantities are of the same order of magnitude if one is less than 10 times as large as the other; the number of magnitudes that the quantities differ is specified to within a power of 10;
is a kind of ratio

3.  magnitude(n = noun.attribute) - relative importance; "a problem of the first magnitude"
is a kind of importance
has particulars: extensiveness, largeness
Derived form verb magnify₁

1.  Extent of dimensions; size; -- applied to things that have length, breadth, and thickness. [1913 Webster]
"Conceive those particles of bodies to be so disposed amongst themselves, that the intervals of empty spaces between them may be equal in magnitude to them all." [1913 Webster]

2.  That which has one or more of the three dimensions, length, breadth, and thickness. [1913 Webster]

3.  Anything of which greater or less can be predicated, as time, weight, force, and the like. [1913 Webster]

4.  Greatness; grandeur. Milton. [1913 Webster]

5.  Greatness, in reference to influence or effect; importance; as, an affair of magnitude. [1913 Webster]
"The magnitude of his designs." [1913 Webster]

6.  See magnitude of a star, below. [PJC]

magnitude, n.
1 largeness.
2 size.
3 importance.
4 a the degree of brightness of a star (see also absolute magnitude, apparent magnitude). b a class of stars arranged according to this (of the third magnitude).

Idiom:
of the first magnitude very important.

Etymology:
ME f. L magnitudo f. magnus great

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, 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  size, magnitude, dimension, bulk, volume, largeness, greatness, expanse, amplitude, mass, proportions, capacity, tonnage, tunnage, cordage, caliber, scantling, turgidity, corpulence, obesity, plumpness, embonpoint, corporation, flesh and blood, lustihood, hugeness, enormity, immensity, monstrosity, giant, Brobdingnagian, Antaeus, Goliath, Gog and Magog, Gargantua, monster, mammoth, Cyclops, cachalot, whale, porpoise, behemoth, leviathan, elephant, hippopotamus, colossus, tun, cord, lump, bulk, block, loaf, mass, swad, clod, nugget, bushel, thumper, whooper, spanker, strapper, Triton among the minnows, mountain, mound, heap, largest portion, full size, life size, large, big, great, considerable, bulky, voluminous, ample, massive, massy, capacious, comprehensive, spacious, mighty, towering, fine, magnificent, corpulent, stout, fat, obese, plump, squab, full, lusty, strapping, bouncing, portly, burly, well-fed, full-grown, corn fed, gram fed, stalwart, brawny, fleshy, goodly, in good case, in good condition, in condition, chopping, jolly, chub faced, chubby faced, lubberly, hulky, unwieldy, lumpish, gaunt, spanking, whacking, whopping, walloping, thumping, thundering, hulking, overgrown, puffy, huge, immense, enormous, mighty, vast, vasty, amplitudinous, stupendous, monster, monstrous, humongous, monumental, elephantine, jumbo, mammoth, gigantic, gigantean, giant, giant like, titanic, prodigious, colossal, Cyclopean, Brobdingnagian, Bunyanesque, Herculean, Gargantuan, infinite, large as life, plump as a dumpling, plump as a partridge, fat as a pig, fat as a quail, fat as butter, fat as brawn, fat as bacon, immeasurable, unfathomable, unplumbed, inconceivable, unimaginable, unheard-of, of cosmic proportions, of epic proportions, the mother of all, teh granddaddy of all.

absolute magnitude, change magnitude, change of magnitude, magnitude relation, order of magnitude