Word.ws English Dictionary

surd

/sɜːd/US/sɝd/

surd noun: an irrational number, especially one expressed using the √ symbol.

Noun

surd (plural surds)

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

Adjective

surd (comparative more surd, superlative most surd)

  1. (obsolete) Lacking the sense of hearing; deaf.
    • …how all Words fall to the Ground, spent upon such a surd and Earless Generation of Men, stupid unto all Instruction…1670s, published 1716, Thomas Browne, Christian Morals, part 3, section 6
  2. (obsolete) unheard
    • To this errour, of blending the ſurd and vocal modes of articulation together, may be added the too frequent uſe of compound articulations both vocal and ſurd.1773, William Kenrick, A New Dictionary of the English Language, section 3, page 5
  3. Involving surds, or irrational numbers; not capable of being expressed in rational numbers.
    • a surd expression or quantity; a surd number
  4. unvoiced; voiceless
    Antonyms:
    sonant

surd meaning in Hindi and Tamil

surd in Hindi

surd, irrational root
करणी karṇī

surd in Tamil

விகிதமுறா மூலம், வல்லொளி, வல்லினம்

Antonyms of surd

Forms of surd

Noun
pluralsurds
Adjective
comparativemore surd
superlativemost surd

Origin of surd

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.

Words formed from surd

Words that rhyme with surd

35 more rhymesFewer rhymes

Questions about surd

What does surd mean?
Surd means an irrational number, especially one expressed using the √ symbol.
What is surd in Hindi?
Surd in Hindi is करणी (karṇī). See Surd meaning in Hindi.
What part of speech is surd?
Surd can be a noun or an adjective.
How do you pronounce surd?
Surd is pronounced /sɜːd/ (UK).
What is the plural of surd?
The plural of surd is surds.

Words near surd in the dictionary

  1. surculi
  2. surculose
  3. surculoside
  4. surculus
  5. surcurrent
  6. surd
  7. Surdila-Greci
  8. surdimutism
  9. surdity
  10. surdization
  11. surdo

Source and license

Adapted from Wiktionary: surd (page history and authors); करणी (Hindi) (page history and authors); surd (Tamil Wiktionary) (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Vealhurl-surd.wav.

Cite this entry: “surd.” Word.ws, https://word.ws/surd. Based on Wiktionary, CC BY-SA 4.0.