ideogram vs logograph

ideogram and logograph both are nouns.

Word	Noun	Adjective	Verb	Adverb
ideogram	Yes	No	No	No
logograph	Yes	No	No	No

As nouns, logograph is a hyponym of ideogram; that is, logograph is a word with a more specific, narrower meaning than ideogram:

ideogram: a graphic character that indicates the meaning of a thing without indicating the sounds used to say it
logograph: a single written symbol that represents an entire word or phrase without indicating its pronunciation

Other hyponyms of ideogram include logogram, emoji.

ideogram (noun)	logograph (noun)
a graphic character that indicates the meaning of a thing without indicating the sounds used to say it	a single written symbol that represents an entire word or phrase without indicating its pronunciation