ideogram vs graphic symbol

ideogram and graphic symbol both are nouns.

Word	Noun	Adjective	Verb	Adverb
ideogram	Yes	No	No	No
graphic symbol	Yes	No	No	No

As nouns, graphic symbol is a hypernym of ideogram; that is, graphic symbol is a word with a broader meaning than ideogram:

ideogram: a graphic character that indicates the meaning of a thing without indicating the sounds used to say it
graphic symbol: a written symbol that is used to represent speech

Other hypernyms of ideogram include character, graph, grapheme.

ideogram (noun)	graphic symbol (noun)
a graphic character that indicates the meaning of a thing without indicating the sounds used to say it	a written symbol that is used to represent speech