ideogram vs logogram

ideogram and logogram both are nouns.

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

As nouns, logogram is a hyponym of ideogram; that is, logogram 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
logogram: a single written symbol that represents an entire word or phrase without indicating its pronunciation

Other hyponyms of ideogram include logograph, emoji.

ideogram (noun)	logogram (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