An ideogram was a character that represented an idea, single thought or concept pictured, without being completely obvious about what this idea is. The term ideography referred to the writing system that ideograms represented, however no written language could function exclusively using ideograms. As a result, many of the characters came to also represent other aspects of language, mainly speech by having characters represent sounds.
While translating the Osaarian cargo manifest acquired in 2153, Hoshi Sato discovered a symbol whose ideography she recognized from a piece of the Xindi probe that crashed on Earth. During her initial analysis, she found at least three of the symbols to be an exact match. (ENT: "Anomaly")