Delta (δ lowercase, Δ uppercase) is the fourth letter of the Greek Alphabet and a common symbol for change or difference in science and math. [1, 2]

Meanings and Uses

• Change in Value: The uppercase symbol (Δ) means the change in a variable. For example, Δ x means the final position minus the initial position. [1, 2, 3]
• Small Change: The lowercase symbol (δ) often represents a very small or infinitesimal change in calculus. [1, 2]
• Math and Science: Lowercase δ is also used for the Kronecker delta in linear algebra, while uppercase Δ represents the discriminant in quadratic equations. [1, 2]