Surd

Net having the sense of hearing; deaf.

Unheard.

Involving surds; not capable of being expressed in rational numbers; radical; irrational; as, a surd expression or quantity; a surd number.

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.

A quantity which can not be expressed by rational numbers; thus, ?2 is a surd.

A surd element of speech. See Surd, a., 4.

a consonant produced without sound from the vocal cords