Greek alphabet vs alpha

Greek alphabet and alpha both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greek alphabet	Yes	No	No	No
alpha	Yes	Yes	No	No

Greek alphabet (noun)	alpha (noun)
the alphabet used by ancient Greeks	the 1st letter of the Greek alphabet
	the beginning of a series or sequence

Greek alphabet (adjective)	alpha (adjective)
	early testing stage of a software or hardware product
	first in order of importance