finial vs decoration

finial and decoration both are nouns.

Word	Noun	Adjective	Verb	Adverb
finial	Yes	No	No	No
decoration	Yes	No	No	No

As nouns, decoration is a hypernym of finial; that is, decoration is a word with a broader meaning than finial:

finial: an ornament at the top of a spire or gable; usually a foliated fleur-de-lis
decoration: something used to beautify

Other hypernyms of finial include ornament, ornamentation.

finial (noun)	decoration (noun)
an ornament at the top of a spire or gable; usually a foliated fleur-de-lis	the act of decorating something (in the hope of making it more attractive)
	something used to beautify
	an award for winning a championship or commemorating some other event