surd

Noun

1. An irrational number, especially one expressed using the √ symbol.
2. A voiceless consonant.

Adj

1. (obsolete) Lacking the sense of hearing; deaf.
2. (obsolete) unheard
3. Involving surds, or irrational numbers; not capable of being expressed in rational numbers.
4. unvoiced; voiceless

Opposite of

sonant

Pronounced as (IPA)

/sɜːd/

Etymology

First attested in the mid 16th century from Latin surdus (“deaf, mute”), used in mathematics for “irrational,” reflecting ἄλογος (álogos, “irrational, speechless”) as found in Euclid, apparently transmitted via Arabic جِذْر أَصَمّ (jiḏr ʔaṣamm, “deaf root”). The phonetic sense, “voiceless,” emerged in the 18th century. Doublet of surdo.

Synonyms

voiceless

unvoiced

hard

voiceless consonant

irrational root

irrational

unreflected

irrational number

voiceless sound

surd root

unvoiced consonant

nonresonant

toneless

radical

uninflected

Translations

sourd

irrational

sorda

stimmlos

irrationale algebraische Zahl

irrationale Wurzel

άφωνο σύμφωνο

ασύμμετρος αριθμός

irrationnel

sourde

sordo

irrazionale

irracjonalny

spółgłoska bezdźwięczna

surdo