footnote vs notation

footnote and notation both are nouns.

Word	Noun	Adjective	Verb	Adverb
footnote	Yes	No	Yes	No
notation	Yes	No	No	No

As nouns, notation is a hypernym of footnote; that is, notation is a word with a broader meaning than footnote:

Other hypernyms of footnote include annotation, note.

footnote (noun)	notation (noun)
a printed note placed below the text on a printed page	the activity of representing something by a special system of marks or characters
	a technical system of symbols used to represent special things
	a comment or instruction (usually added)

footnote (verb)	notation (verb)
add explanatory notes to or supply with critical comments