Definition of surd in English:


Line breaks: surd
Pronunciation: /səːd


  • 1 Mathematics (Of a number) irrational.
  • 2 Phonetics (Of a speech sound) uttered with the breath and not the voice (e.g. f, k, p, s, t).


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  • 1 Mathematics A surd number, especially the irrational root of an integer.
    More example sentences
    • They were learning about surds in maths, supposedly one of the hardest subjects.
    • I don't care about rationalising denominators with surds in them, and I don't care that by using maths induction you can prove many equations to be right or wrong.
    • In the conventional school education in India, we are asked to do some problems involving surds (radicals).
  • 2 Phonetics A surd consonant.


mid 16th century: from Latin surdus 'deaf, mute'; as a mathematical term, translating Greek (Euclid) alogos 'irrational, speechless', apparently via Arabic jiḏr aṣamm, literally 'deaf root'. sense 2 of the adjective dates from the mid 18th century.

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