*undu*

[ a trade name, from Carbon + corundum. ] A beautiful crystalline compound, silicon carbide (SiC), consisting of carbon and silicon in combination; -- also called carbon silicide. It is made by heating carbon and sand together in an electric furnace. The commercial article is dark-colored and iridescent. It is harder than emery, and is used as an abrasive. [ Webster 1913 Suppl. ]

{ or }. Cloth or paper covered with powdered carborundum; -- a foprm of sandpaper. [ Webster 1913 Suppl. +PJC ]

v. t. [ Pref. circum- + undulate. ] To flow round, as waves. [ R. ] [ 1913 Webster ]

n.; pl. Corundums [ Also corindon. ] [ From Hind. kurand corundum stone. ] (Min.) The mineral alumina (Al2O3), as found native in a crystalline state. Transparent varieties are used as gemstones, including sapphire, which is the fine blue variety; the oriental ruby, or red sapphire; the oriental amethyst, or purple sapphire; and adamantine spar, the hair-brown variety. It is the hardest substance found native, next to the diamond. [ 1913 Webster +PJC ]

☞ The name corundum is sometimes restricted to the non-transparent or coarser kinds. Emery is a dark-colored granular variety, usually admixed with magnetic iron ore. [ 1913 Webster ]

n. (Med.) The bark of a South American vine (Gonolobus Condurango) of the Milkweed family. It has been supposed, but erroneously, to be a cure for cancer. [ Written also condurango. ] [ 1913 Webster ]

‖n. [ Native name. ] (Zool.) An East Indian carnivorous mammal (Prionodon gracilis), resembling the civets, but without scent pouches. It is handsomely spotted. [ 1913 Webster ]

‖n. [ L., bottom. ] (Anat.) The bottom or base of any hollow organ; as, the fundus of the bladder; the fundus of the eye; the fundus of the uterus. [ 1913 Webster ]

n. [ Cf. Sp. mondongo paunch, tripe, black pudding. ] A stinking tobacco. [ 1913 Webster ]

n. [ Cf. Rondure. ] Roundness; a round or circle. [ Obs. ] Shak. [ 1913 Webster ]

n. [ Trade name ] A form of silicon carbide, produced in the electric furnace, possessing great hardness, and high electrical resistance, and not subject to oxidation below 2880° F., or 1600° C. [ Webster 1913 Suppl. ]

a. Indubitable; as, an undubitable principle. [ Obs. ] Locke. [ 1913 Webster ]

a. 1. Not due; not yet owing; as, an undue debt, note, or bond. [ 1913 Webster ]

2. Not right; not lawful or legal; improper; as, an undue proceeding. Bacon. [ 1913 Webster ]

3. Not agreeable to a rule or standard, or to duty; disproportioned; excessive; immoderate; inordinate; as, an undue attachment to forms; an undue rigor in the execution of law. [ 1913 Webster ]

Undue influence (Law), any improper or wrongful constraint, machination, or urgency of persuasion, by which one's will is overcome and he is induced to do or forbear an act which he would not do, or would do, if left to act freely. Abbott. [ 1913 Webster ]

n. The quality of being undue. [ 1913 Webster ]

v. t. [ 1st pref. un- + duke. ] To deprive of dukedom. Swift. [ 1913 Webster ]

a. Undulating. [ R. ] [ 1913 Webster ]

a. [ See Undulate. ] Moving like waves; undulatory. [ Obs. ] Sir T. Browne. [ 1913 Webster ]

a. [ L. undulatus undulated, wavy, a dim. from unda a wave; cf. AS. &unr_;&unr_;, Icel. unnr; perhaps akin to E. water. Cf. Abound, Inundate, Redound, Surround. ] Same as Undulated. [ 1913 Webster ]

v. t. [ imp. & p. p. Undulated p. pr. & vb. n. Undulating. ] To cause to move backward and forward, or up and down, in undulations or waves; to cause to vibrate. [ 1913 Webster ]

Breath vocalized, that is, vibrated and undulated. Holder. [ 1913 Webster ]

v. i. To move in, or have, undulations or waves; to vibrate; to wave; as, undulating air. [ 1913 Webster ]

a. 1. Resembling, or in the nature of, waves; having a wavy surface; undulatory. [ 1913 Webster ]

2. (Bot.) Waved obtusely up and down, near the margin, as a leaf or corolla; wavy. [ 1913 Webster ]

3. (Zool.) Formed with elevations and depressions resembling waves; having wavelike color markings; as, an undulated shell. [ 1913 Webster ]

a. Rising and falling like waves; resembling wave form or motion; undulatory; rolling; wavy; as, an undulating medium; undulating ground. -- Un"du*la`ting*ly. adv. [1913 Webster]

n. [ Cf. F. ondulation. ] 1. The act of undulating; a waving motion or vibration; as, the undulations of a fluid, of water, or of air; the undulations of sound. [ 1913 Webster ]

2. A wavy appearance or outline; waviness. Evelyn. [ 1913 Webster ]

3. (Mus.) (a) The tremulous tone produced by a peculiar pressure of the finger on a string, as of a violin. (b) The pulsation caused by the vibrating together of two tones not quite in unison; -- called also beat. [ 1913 Webster ]

4. (Physics) A motion to and fro, up and down, or from side to side, in any fluid or elastic medium, propagated continuously among its particles, but with no translation of the particles themselves in the direction of the propagation of the wave; a wave motion; a vibration. [ 1913 Webster ]

n. One who advocates the undulatory theory of light. Whewell. [ 1913 Webster ]

a. Consisting in, or accompanied by, undulations; undulatory. [ 1913 Webster ]

a. [ Cf. F. ondulatoire. ] Moving in the manner of undulations, or waves; resembling the motion of waves, which successively rise or swell rise or swell and fall; pertaining to a propagated alternating motion, similar to that of waves. [ 1913 Webster ]

Undulatory theory, or
Wave theory (of light) (Opt.), that theory which regards the various phenomena of light as due to undulations in an ethereal medium, propagated from the radiant with immense, but measurable, velocities, and producing different impressions on the retina according to their amplitude and frequency, the sensation of brightness depending on the former, that of color on the latter. The undulations are supposed to take place, not in the direction of propagation, as in the air waves constituting sound, but transversely, and the various phenomena of refraction, polarization, interference, etc., are attributable to the different affections of these undulations in different circumstances of propagation. It is computed that the frequency of the undulations corresponding to the several colors of the spectrum ranges from 458 millions of millions per second for the extreme red ray, to 727 millions of millions for the extreme violet, and their lengths for the same colors, from the thirty-eight thousandth to the sixty thousandth part of an inch. The theory of ethereal undulations is applicable not only to the phenomena of light, but also to those of heat. [ 1913 Webster ]

v. t. [ 1st pref. un- + dull. ] To remove the dullness of; to clear. [ Obs. ] Whitlock. [ 1913 Webster ]

a. Undulating; undulatory. [ 1913 Webster ]

adv. In an undue manner. [ 1913 Webster ]

v. t. [ 1st pref. un- + dumpish. ] To relieve from the dumps. [ Obs. ] Fuller. [ 1913 Webster ]

v. t. [ 1st pref. un- + dust. ] To free from dust. [ Obs. ] [ 1913 Webster ]