subprogram vs software

subprogram and software both are nouns.

Word	Noun	Adjective	Verb	Adverb
subprogram	Yes	No	No	No
software	Yes	No	No	No

As nouns, software is a hypernym of subprogram; that is, software is a word with a broader meaning than subprogram:

subprogram: a set sequence of steps, part of larger computer program
software: (computer science) written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory

Other hypernyms of subprogram include computer software, package, software package, software program, software system.

subprogram (noun)	software (noun)
a set sequence of steps, part of larger computer program	(computer science) written programs or procedures or rules and associated documentation pertaining to the operation of a computer system and that are stored in read/write memory