adornment vs ornamentation

adornment and ornamentation both are nouns.

Word	Noun	Adjective	Verb	Adverb
adornment	Yes	No	No	No
ornamentation	Yes	No	No	No

As nouns, ornamentation is a hypernym of adornment; that is, ornamentation is a word with a broader meaning than adornment:

adornment: a decoration of color or interest that is added to relieve plainness
ornamentation: something used to beautify

Other hypernyms of adornment include decoration, ornament.

adornment (noun)	ornamentation (noun)
the action of decorating yourself with something colorful and interesting	the act of adding extraneous decorations to something
a decoration of color or interest that is added to relieve plainness	something used to beautify
	the state of being ornamented