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.
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.
Undulationist
(Un`du*la"tion*ist), n. One who advocates the undulatory theory of light. Whewell.
Undulative
(Un"du*la*tive) a. Consisting in, or accompanied by, undulations; undulatory.
Undulatory
(Un"du*la*to*ry) 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.
Undulatory theory, or Wave theory (of light) (Opt.), that theory which regards its various phenomena
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.
Undull
(Un*dull") v. t. [1st pref. un- + dull.] To remove the dullness of; to clear. [Obs.] Whitlock.
Undulous
(Un"du*lous) a. Undulating; undulatory.
Unduly
(Un*du"ly) adv. In an undue manner.
Undumpish
(Un*dump"ish) v. t. [1st pref. un- + dumpish.] To relieve from the dumps. [Obs.] Fuller.
Undust
(Un*dust") v. t. [1st pref. un- + dust.] To free from dust. [Obs.]
Undwellable
(Un*dwell"a*ble) a. Uninhabitable. [Obs.] "A land undwellable." Wyclif.
Undwelt
(Un*dwelt") a. Not lived (in); — with in.
Undying
(Un*dy"ing) a. Not dying; imperishable; unending; immortal; as, the undying souls of men.
Uneared
(Un*eared") a. Not eared, or plowed. Shak.
Unearned
(Un*earned") a. Not earned; not gained by labor or service.
Unearned increment (Polit. Econ.), a increase in the value of land due to no labor or expenditure on
the part of the owner, but to natural causes, such as the increase of population, the growth of a town in
the vicinity, or the like. Some hold that this should belong to the nation.
