\ ˈsərd How to pronounce surd (audio) \

Definition of surd

 (Entry 1 of 2)

1 : lacking sense : irrational surd conceits of scripture's sense— Thomas Jackson
2 : voiceless used of speech sounds



Definition of surd (Entry 2 of 2)

1a : an irrational root (such as √3)
2 : a surd speech sound

Making Sense of Absurd

Absurd contains the rarer related adjective surd, which, like absurd, derives from the Latin surdus ("deaf, silent, stupid").

Surd can mean "lacking sense or irrational," much like absurd:

While the grandparents might scratch their heads at the Star Wars references, the actors and perhaps some younger parents likely delighted in manic, jumbled and surd structure of the play.
–Patrick Clement, Kiowa County Signal (Greensburg, Kansas), 23 Jan. 2013

Absurd, however, stresses a lack of logical sense or harmonious agreement, of parts (such as a premise and a conclusion) not fitting together. In philosophy, it describes the problem of trying to distill meaning from one's experiences. In A Discourse on Novelty and Creation (1975), Carl R. Hausman writes, "There is an incongruity, an inconsistency, a conflict with a context that appears as lawful, orderly experience. As [Albert] Camus points out, absurdity 'springs from a comparison,' a comparison between two aspects of reality which seem to be out of harmony."

Did You Know?


Both surd and its more common cousin absurd come from the Latin word surdus, meaning "unhearing, deaf, muffled, or dull." Absurd traveled through Middle French before arriving in English in the early 16th century. Its arrival preceded by a few decades the adoption of the noun version of our featured word directly from Latin, which referred to an irrational root, such as √3. By the early 17th century surd had gained a more general application. The adjective describes speech sounds that are not voiced-for example, the \p\ sound, as opposed to the voiced \b.

First Known Use of surd


1610, in the meaning defined at sense 1


1557, in the meaning defined at sense 1a

History and Etymology for surd


Latin surdus deaf, silent, stupid

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Cite this Entry

“Surd.” Dictionary, Merriam-Webster, Accessed 17 Apr. 2021.

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