observance vs pageant

observance and pageant both are nouns.

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

As nouns, pageant is a hyponym of observance; that is, pageant is a word with a more specific, narrower meaning than observance:

observance (noun)	pageant (noun)
the act of observing; taking a patient look	an elaborate representation of scenes from history etc; usually involves a parade with rich costumes
conformity with law or custom or practice etc.	a rich and spectacular ceremony
the act of noticing or paying attention
a formal event performed on a special occasion