subscript vs grapheme

subscript and grapheme both are nouns.

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

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

subscript: a character or symbol set or printed or written beneath or slightly below and to the side of another character
grapheme: a written symbol that is used to represent speech

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

subscript (noun)	grapheme (noun)
a character or symbol set or printed or written beneath or slightly below and to the side of another character	a written symbol that is used to represent speech

subscript (adjective)	grapheme (adjective)
written or printed below and to one side of another character