- voiceless (opposed to sonant).
- (of a quantity) not capable of being expressed in rational numbers; irrational.
- a voiceless consonant (opposed to sonant).
- a surd quantity.
- an expression containing one or more irrational roots of numbers, such as 2√3 + 3√2 + 6
- a voiceless consonant, such as (t)
- of or relating to a surd
