First letter of the Greek Alphabet
Used as an adjective to indicate the first or most significant occurrence of something. Examples include:
alpha male - the head of a group of animals, such as gorillas
alpha geek - a similar use, referring to any person considered pre-eminent amongst geeks, such as Linus Torvalds
alpha version or alpha release - the first release of a computer programme or other product, likely to be very unstable but useful for demonstrating internally and to select customers.
alpha - a microprocessor from DEC.