An ideogram is a character that represents an idea, single thought or concept pictured, without being completely obvious about what this idea is. The term ideography refers to the writing system that ideograms represent, however no written language can function exclusively using ideograms: As a result many of the characters come 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")