alpha

Concise Oxford English Dictionary © 2008 Oxford University Press:
alpha /ˈalfə/

▶noun

• 1 the first letter of the Greek alphabet (Α, α), transliterated as ‘a’.

  ■ [as modifier] denoting the first of a series of items or categories.

  ■ [as modifier] denoting the dominant animal or person in a group: an alpha male.

  ■ Brit. a first-class mark given for a piece of work.

• 2 a code word representing the letter A, used in radio communication.

– phrases
alpha and omega the beginning and the end (used by Christians as a title for Jesus).

– origin via L. from Gk.