surd

• POS: Adjective, Noun

CIDE DICTIONARY

surd, a. [L. surdus deaf (whence the meaning, deaf to reason, irrational), perhaps akin to E. swart. Cf. Sordine.].

•  Net having the sense of hearing; deaf.  Sir T. Browne.  [1913 Webster]
•  Unheard.  Kenrick.  [1913 Webster]
•  Involving surds; not capable of being expressed in rational numbers; radical; irrational; as, a surd expression or quantity; a surd number.  [1913 Webster]
•  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, 1913 Webster]

surd, n. 

•  A quantity which can not be expressed by rational numbers; thus, √2 is a surd.  [1913 Webster]
•  A surd element of speech. See Surd, a., 4.  [1913 Webster]

OXFORD DICTIONARY

surd, adj. & n.
--adj.
1 Math. (of a number) irrational.
2 Phonet. (of a sound) uttered with the breath and not the voice (e.g. f, k, p, s, t).
--n.
1 Math. a surd number, esp. the root of an integer.
2 Phonet. a surd sound.

Etymology

L surdus deaf, mute: sense 1 by mistransl. into L of Gk alogos irrational, speechless, through Arab. jadr asamm deaf root

THESAURUS

surd

Gaussian integer, accented, algebraic number, algorismic, algorithmic, aliquot, allophone, alveolar, apical, apico-alveolar, apico-dental, articulated, articulation, aspiration, assimilated, assimilation, back, barytone, bilabial, broad, cacuminal, cardinal, cardinal number, central, cerebral, check, checked, close, complex number, consonant, consonantal, continuant, deaf, deaf and dumb, deaf-eared, deaf-mute, deafened, decimal, defective number, dental, differential, digital, diphthong, dissimilated, dissimilation, dorsal, dull-eared, earless, epenthetic vowel, even, even number, explosive, exponential, figural, figurate, figurative, finite, finite number, flat, fraction, fractional, front, glide, glossal, glottal, glottalization, guttural, hard, hard of hearing, heavy, high, imaginary, imaginary number, impair, impossible, infinite, infinity, integer, integral, intonated, irrational, irrational number, labial, labialization, labiodental, labiovelar, laryngeal, lateral, lax, light, lingual, liquid, logarithmic, logometric, low, manner of articulation, mid, mixed number, modification, monophthong, monophthongal, morphophoneme, mute, muted, narrow, nasal, nasalized, negative, numeral, numerary, numerative, numeric, occlusive, odd, open, ordinal, oxytone, pair, palatal, palatalized, parasitic vowel, peak, pharyngeal, pharyngealization, pharyngealized, phone, phoneme, phonemic, phonetic, phonic, pitch, pitched, plosive, polygonal number, positive, possible, posttonic, prime, prime number, prothetic vowel, pure imaginary, radical, rational, rational number, real, real number, reciprocal, rectangular number, retroflex, round number, rounded, segmental phoneme, semivowel, serial number, soft, sonant, sonority, speech sound, stone-deaf, stop, stopped, stressed, strong, stunned, submultiple, syllabic, syllabic nucleus, syllabic peak, syllable, tense, thick, thick of hearing, throaty, tonal, tone-deaf, tonic, transcendental, transcendental number, transfinite number, transition sound, triphthong, twangy, unaccented, unhearing, unrounded, unstressed, velar, vocable, vocalic, vocoid, voice, voiced, voiced sound, voiceless, voiceless sound, voicing, vowel, vowellike, weak, whole number, wide, word-deaf

ROGET THESAURUS

surd

Number

N number, symbol, numeral, figure, cipher, digit, integer, counter, round number, formula, function, series, sum, difference, complement, subtrahend, product, multiplicand, multiplier, multiplicator, coefficient, multiple, dividend, divisor, factor, quotient, submultiple, fraction, rational number, surd, irrational number, transcendental number, mixed number, complex number, complex conjugate, numerator, denominator, decimal, circulating decimal, repetend, common measure, aliquot part, prime number, prime, relative prime, prime factor, prime pair, reciprocal, totient, binary number, octal number, hexadecimal number, permutation, combination, variation, election, ratio, proportion, comparison, progression, arithmetical progression, geometrical progression, harmonical progression, percentage, permilage, figurate numbers, pyramidal numbers, polygonal numbers, power, root, exponent, index, logarithm, antilogarithm, modulus, base, differential, integral, fluxion, fluent, numeral, complementary, divisible, aliquot, reciprocal, prime, relatively prime, fractional, decimal, figurate, incommensurable, proportional, exponential, logarithmic, logometric, differential, fluxional, integral, totitive, positive, negative, rational, irrational, surd, radical, real, complex, imaginary, finite, infinite, impossible, numerically, modulo, number, symbol, numeral, figure, cipher, digit, integer, counter, round number, formula, function, series, sum, difference, complement, subtrahend, product, multiplicand, multiplier, multiplicator, coefficient, multiple, dividend, divisor, factor, quotient, submultiple, fraction, rational number, surd, irrational number, transcendental number, mixed number, complex number, complex conjugate, numerator, denominator, decimal, circulating decimal, repetend, common measure, aliquot part, prime number, prime, relative prime, prime factor, prime pair, reciprocal, totient, binary number, octal number, hexadecimal number, permutation, combination, variation, election, ratio, proportion, comparison, progression, arithmetical progression, geometrical progression, harmonical progression, percentage, permilage, figurate numbers, pyramidal numbers, polygonal numbers, power, root, exponent, index, logarithm, antilogarithm, modulus, base, differential, integral, fluxion, fluent, numeral, complementary, divisible, aliquot, reciprocal, prime, relatively prime, fractional, decimal, figurate, incommensurable, proportional, exponential, logarithmic, logometric, differential, fluxional, integral, totitive, positive, negative, rational, irrational, surd, radical, real, complex, imaginary, finite, infinite, impossible, numerically, modulo.

Deafness

N deafness, hardness of hearing, surdity, inaudibility, inaudibleness, deaf, earless, surd, hard of hearing, dull of hearing, deaf-mute, stunned, deafened, stone deaf, deaf as a post, deaf as an adder, deaf as a beetle, deaf as a trunkmaker, inaudible, out of hearing, hear no evil, (6) Light (i) LIGHT IN GENERAL.