Alpha/ˈælfə/ Definition 1 of 5Pro Tip 1/2Greek Reference Use 'alpha' to reference the beginning or the first in any series, inspired by its Greek origin. He scored alpha grade in the starting test. Pro Tip 2/2Not Alpha-beta 'Alpha' shouldn't be confused with 'alphabet,' despite being its first two letters. She learned alpha, not the rest of the alphabet yet.