from The American Heritage® Dictionary of the English Language, 4th Edition
- n. Mathematics An irrational number, such as √2.
- n. Linguistics A voiceless sound in speech.
- adj. Linguistics Voiceless, as a sound.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An irrational number, especially one expressed using the √ symbol.
- n. A voiceless consonant.
from the GNU version of the Collaborative International Dictionary of English
- adj. Net having the sense of hearing; deaf.
- adj. Unheard.
- adj. Involving surds; not capable of being expressed in rational numbers; radical; irrational.
- adj. Uttered, as an element of speech, without tone, or proper vocal sound; voiceless; unintonated; nonvocal; atonic; whispered; aspirated; sharp; hard, as f, p, s, etc.; -- opposed to sonant. See Guide to Pronunciation, §§169, 179, 180.
- n. A quantity which can not be expressed by rational numbers.
- n. A surd element of speech. See Surd, a., 4.
from The Century Dictionary and Cyclopedia
- Not having the sense of hearing; deaf.
- That cannot be discriminated by the ear (?).
- In mathematics, not capable of being expressed in rational numbers: as, a surd expression, quantity, or number. See II., 1.
- In phonetics, uttered with breath and not with voice; devoid of vocality; not sonant: toneless: specifically applied to the breathed or non-vocal consonants of the alphabet. See II., 2.
- Meaningless; senseless.
- n. In mathematics, a quantity not expressible as the ratio of two whole numbers, as √ 2, or the ratio of the circumference of a circle to the diameter.
- n. In phonetics, a consonantal sound uttered with breath and not with voice; a non-sonant consonant; a non-vocal alphabetic utterance, as p, f, s, t, k, as opposed to b, v, z, d, g, which are sonants or vocals.
- To render dim or soft; mute.
- Containing or involving a surd : thus [1 + ½] ½ is a surd expression but not a surd, since 1 + ½ is not a rational expression.
- n. In mathematics: An indicated root whose value is irrational, but whose radicand is rational, as ½. A surd is quadratic, cubic, of order n, according as its exponent is ½, ⅓, 1/n;.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a consonant produced without sound from the vocal cords
- adj. produced without vibration of the vocal cords
Medieval Latin surdus, speechless, surd (translation of Arabic (jaḏr) 'aṣamm, deaf (root), surd, translation of Greek alogos, speechless, surd), from Latin.(American Heritage® Dictionary of the English Language, Fourth Edition)