honouring vs observance

honouring and observance both are nouns.

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

As nouns, honouring and observance are synonyms defined as:

honouring and observance: conformity with law or custom or practice etc.

Other synonyms of honouring include honoring.

honouring (noun)	observance (noun)
conformity with law or custom or practice etc.	the act of observing; taking a patient look
	conformity with law or custom or practice etc.
	the act of noticing or paying attention
	a formal event performed on a special occasion