floral arrangement vs ornament

floral arrangement and ornament both are nouns.

Word	Noun	Adjective	Verb	Adverb
floral arrangement	Yes	No	No	No
ornament	Yes	No	Yes	No

As nouns, ornament is a hypernym of floral arrangement; that is, ornament is a word with a broader meaning than floral arrangement:

Other hypernyms of floral arrangement include decoration, ornamentation, arrangement.

floral arrangement (noun)	ornament (noun)
a decorative arrangement of flowers	something used to beautify

floral arrangement (verb)	ornament (verb)
	make more attractive by adding ornament, colour, etc.
	be an ornament to