observance vs abidance

observance and abidance both are nouns.

Word	Noun	Adjective	Verb	Adverb
observance	Yes	No	No	No
abidance	Yes	No	No	No

As nouns, abidance is a hypernym of observance; that is, abidance is a word with a broader meaning than observance:

Other hypernyms of observance include compliance, conformation, conformity.

observance (noun)	abidance (noun)
the act of observing; taking a patient look	the act of abiding (enduring without yielding)
conformity with law or custom or practice etc.	the act of dwelling in a place
the act of noticing or paying attention	acting according to certain accepted standards
a formal event performed on a special occasion