1. an irrational number, especially a square root that cannot be expressed as a ratio of integers
Usage: mathematics

1. lacking the power of speech; mute
Usage: archaic
2. pronounced without vibration of the vocal cords
Usage: phonetics

Examples

• The square root of 2 is a surd because it cannot be written as a simple fraction.
• In algebra class, we learned to simplify expressions containing surds.
• The mathematician explained that π is a surd, not a rational number.
• The consonant ‘p’ is a surd sound in English phonetics.
• Students often struggle with calculations involving surds in geometry.