practical application vs usage

practical application and usage both are nouns.

Word	Noun	Adjective	Verb	Adverb
practical application	Yes	No	No	No
usage	Yes	No	No	No

As nouns, usage is a hypernym of practical application; that is, usage is a word with a broader meaning than practical application:

practical application: the act of bringing something to bear; using it for a particular purpose
usage: the act of using

Other hypernyms of practical application include employment, exercise, use, utilisation, utilization.

practical application (noun)	usage (noun)
the act of bringing something to bear; using it for a particular purpose	the act of using
	accepted or habitual practice
	the customary manner in which a language (or a form of a language) is spoken or written