master file vs main file

master file and main file both are nouns.

Word	Noun	Adjective	Verb	Adverb
master file	Yes	No	No	No
main file	Yes	No	No	No

As nouns, master file and main file are synonyms defined as:

master file and main file: (computer science) a computer file that is used as the authority in a given job and that is relatively permanent

master file (noun)	main file (noun)
(computer science) a computer file that is used as the authority in a given job and that is relatively permanent	(computer science) a computer file that is used as the authority in a given job and that is relatively permanent