[səːd], (Adjective)

Definitions:
- (of a number) irrational

- (of a speech sound) uttered with the breath and not the voice (e.g. f, k, p, s, t)


Phrases:

Origin:
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’. surd dates from the mid 18th century

[səːd], (Noun)

Definitions:
- a surd number, especially the irrational root of an integer

- a surd consonant


Phrases:

Origin:
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’. surd dates from the mid 18th century