Modulus \Mod"u*lus\, n.; pl. Moduli. [L., a small measure. See Module, n.] (Math., Mech., & Physics) A quantity or coefficient, or constant, which expresses the measure of some specified force, property, or quality, as of elasticity, strength, efficiency, etc.; a parameter. Modulus of a machine, a formula expressing the work which a given machine can perform under the conditions involved in its construction; the relation between the work done upon a machine by the moving power, and that yielded at the working points, either constantly, if its motion be uniform, or in the interval of time which it occupies in passing from any given velocity to the same velocity again, if its motion be variable; -- called also the efficiency of the machine. --Mosley. --Rankine. Modulus of a system of logarithms (Math.), a number by which all the Napierian logarithms must be multiplied to obtain the logarithms in another system. Modulus of elasticity. (a) The measure of the elastic force of any substance, expressed by the ratio of a stress on a given unit of the substance to the accompanying distortion, or strain. (b) An expression of the force (usually in terms of the height in feet or weight in pounds of a column of the same body) which would be necessary to elongate a prismatic body of a transverse section equal to a given unit, as a square inch or foot, to double, or to compress it to half, its original length, were that degree of elongation or compression possible, or within the limits of elasticity; -- called also Young's modulus. Modulus of rupture, the measure of the force necessary to break a given substance across, as a beam, expressed by eighteen times the load which is required to break a bar of one inch square, supported flatwise at two points one foot apart, and loaded in the middle between the points of support. --Rankine.

Rupture \Rup"ture\ (?; 135), n. [L. ruptura, fr. rumpere, ruptum to break: cf. F. rupture. See Reave, and cf. Rout a defeat.] 1. The act of breaking apart, or separating; the state of being broken asunder; as, the rupture of the skin; the rupture of a vessel or fiber; the rupture of a lutestring. --Arbuthnot. Hatch from the egg, that soon, Bursting with kindly rupture, forth disclosed Their callow young. --Milton. 2. Breach of peace or concord between individuals; open hostility or war between nations; interruption of friendly relations; as, the parties came to a rupture. He knew that policy would disincline Napoleon from a rupture with his family. --E. Everett. 3. (Med.) Hernia. See Hernia. 4. A bursting open, as of a steam boiler, in a less sudden manner than by explosion. See Explosion. Modulus of rupture. (Engin.) See under Modulus. Syn: Fracture; breach; break; burst; disruption; dissolution. See Fracture.

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