What is the first letter of the Greek alphabet?

The first letter of the Greek alphabet is Alpha.

Alpha is written Α in uppercase and α in lowercase. It occupies the first position in the 24-letter Greek alphabet and has the numeral value one in the Greek numeral system. The letter’s place at the beginning also helped give “alpha” its broader meaning of first, primary, or leading.

Greek adopted most of its alphabet from the Phoenician alphabet in the early 8th century BC. Alpha developed from Phoenician aleph, whose name is associated with “ox.” Unlike its Phoenician predecessor, which represented a consonantal sound, Greek used alpha for a vowel—a major innovation in alphabetic writing.

Alpha is the source of the Latin letter A and influenced the Cyrillic letter А. It is also famous in the expression “alpha and omega,” which pairs the first and last Greek letters. In mathematics and science, α is widely used as a symbol, but those later technical meanings do not change its position in the alphabet.