reusable routine vs routine

reusable routine and routine both are nouns.

Word	Noun	Adjective	Verb	Adverb
reusable routine	Yes	No	No	No
routine	Yes	Yes	No	No

As nouns, routine is a hypernym of reusable routine; that is, routine is a word with a broader meaning than reusable routine:

Other hypernyms of reusable routine include function, procedure, subprogram, subroutine.

reusable routine (noun)	routine (noun)
a routine that can be loaded once and executed repeatedly	an unvarying or habitual method or procedure
	a set sequence of steps, part of larger computer program
	a short performance that is part of a longer program

reusable routine (adjective)	routine (adjective)
	found in the ordinary course of events