1. The fifth letter of the Greek alphabet, represented by the symbol ε or E.
Usage: commonly used in mathematics and science
2. A very small or negligible quantity; something infinitesimal.
Usage: mathematics and technical contexts

Examples

• The Greek alphabet begins with alpha and continues through beta, gamma, delta, and epsilon.
• In calculus, epsilon is often used to represent an arbitrarily small positive number.
• The engineer dismissed the measurement error as epsilon—too small to matter.
• The symbol ε appears frequently in mathematical proofs and scientific equations.
• Students learning Greek letters must memorize epsilon as the fifth letter.