[ surd ]
/ sɜrd /


Phonetics. voiceless (opposed to sonant).
Mathematics. (of a quantity) not capable of being expressed in rational numbers; irrational.


Phonetics. a voiceless consonant (opposed to sonant).
Mathematics. a surd quantity.

Origin of surd

First recorded in 1545–55, surd is from the Latin word surdus dull-sounding, mute, deaf Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020

Examples from the Web for surd

British Dictionary definitions for surd

/ (sɜːd) /


maths an expression containing one or more irrational roots of numbers, such as 2√3 + 3√2 + 6
phonetics a voiceless consonant, such as (t)


of or relating to a surd

Word Origin for surd

C16: from Latin surdus muffled
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012