discontinuance vs ending

discontinuance and ending both are nouns.

Word	Noun	Adjective	Verb	Adverb
discontinuance	Yes	No	No	No
ending	Yes	No	No	No

As nouns, ending is a hypernym of discontinuance; that is, ending is a word with a broader meaning than discontinuance:

discontinuance: the act of discontinuing or breaking off; an interruption (temporary or permanent)
ending: the act of ending something

Other hypernyms of discontinuance include conclusion, termination.

discontinuance (noun)	ending (noun)
the act of discontinuing or breaking off; an interruption (temporary or permanent)	the act of ending something
	the end of a word (a suffix or inflectional ending or final morpheme)
	the last section of a communication
	event whose occurrence ends something
	the point in time at which something ends