Quantity (?), n.; pl. Quantities (#). [F. quantite, L. quantitas, fr. quantus bow great, how much, akin to quam bow, E. how, who. See Who.]
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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. Hence, in specific uses: (a) (Logic) The extent or extension of a general conception, that is, the number of species or individuals to which it may be applied; also, its content or comprehension, that is, the number of its constituent qualities, attributes, or relations. (b) (Gram.) The measure of a syllable; that which determines the time in which it is pronounced; as, “the long or short quantity of a vowel or syllable”. (c) (Mus.) The relative duration of a tone.
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2. That which can be increased, diminished, or measured; especially (Math.), anything to which mathematical processes are applicable.
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☞ 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.
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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”.
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The quantity of extensive and curious information which he had picked up during many months of desultory, but not unprofitable, study. Macaulay.
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Quantity of estate (Law), its time of continuance, or degree of interest, as in fee, for life, or for years. Wharton (Law Dict. ) -- Quantity of matter, in a body, its mass, as determined by its weight, or by its momentum under a given velocity. -- Quantity of motion (Mech.), in a body, the relative amount of its motion, as measured by its momentum, varying as the product of mass and velocity. -- Known quantities (Math.), quantities whose values are given. -- Unknown quantities (Math.), quantities whose values are sought.
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