surd

/sɜːrd/
noun
  1. A number that cannot be expressed as a simple fraction, such as the square root of 2.
    • In math class, we learned that √3 is a surd.
    • The teacher explained that surds have infinite non-repeating decimals.
    • Simplifying surds is an important skill in algebra.
  2. A speech sound that is produced without vibration of the vocal cords, like 'p', 't', or 'k'.
    • In phonetics, the sound 's' is a surd.
    • The difference between a surd and a sonant is whether the vocal cords vibrate.
    • Linguists classify surds as voiceless consonants.