superscript vs grapheme

superscript and grapheme both are nouns.

Word	Noun	Adjective	Verb	Adverb
superscript	Yes	Yes	No	No
grapheme	Yes	No	No	No

As nouns, grapheme is a hypernym of superscript; that is, grapheme is a word with a broader meaning than superscript:

superscript: a character or symbol set or printed or written above and immediately to one side of another character
grapheme: a written symbol that is used to represent speech

Other hypernyms of superscript include character, graph, graphic symbol.

superscript (noun)	grapheme (noun)
a character or symbol set or printed or written above and immediately to one side of another character	a written symbol that is used to represent speech

superscript (adjective)	grapheme (adjective)
written or printed above and to one side of another character