surd Meaning, Definition & Usage

  1. noun a consonant produced without sound from the vocal cords
    voiceless consonant.
  2. adjective produced without vibration of the vocal cords
    voiceless; unvoiced; hard.
    • unvoiced consonants such as `p' and `k' and `s'

WordNet

Surd adjective
Etymology
L. surdus deaf (whence the meaning, deaf to reason, irrational), perhaps akin to E. swart. Cf. Sordine.
Definitions
  1. Net having the sense of hearing; deaf. Obs. "A surd . . . generation." Sir T. Browne.
  2. Unheard. Obs. Kenrick.
  3. (Math.) Involving surds; not capable of being expressed in rational numbers; radical; irrational; as, a surd expression or quantity; a surd number.
  4. (Phonetics) Uttered, as an element of speech, without tone, or proper vocal sound; voiceless; unintonated; nonvocal; atonic; whispered; aspirated; sharp; hard, as f, p, s, etc.; -- opposed to sonant. See Guide to Pronunciation, §§169, 179, 180.
Surd noun
Definitions
(Math.)
  1. A quantity which can not be expressed by rational numbers; thus, *2 is a surd.
  2. (Phon.) A surd element of speech. See Surd, a., 4.

Webster 1913