noun · rare

surd

surd · surds

An irrational number, especially one expressed using the √ symbolAn irrational number, especially one expressed using the √ symbol.

UK/sɜːd/US/sɝd/

Meaning

2 senses

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

More definitions

a consonant produced without sound from the vocal cords

Origin

First attested in the mid 16th century from Latin surdus (“deaf, mute”), used in mathemati

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.

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