Meaning of SURD in English

SURD

[surd] adj [L surdus deaf, silent, stupid] (1551) 1: lacking sense: irrational "the ~ mystery and the strange forces of existence --D. C. Williams"

2: voiceless--used of speech sounds

[2]surd n (1557) 1 a: an irrational root b: irrational number

2: a surd speech sound

Merriam-Webster English vocab.      Английский словарь Merriam Webster.