| The term ideogram means a written symbol or sign that expresses an idea directly, rather than through the intermediary of words. An ideogram is usually pictographic in origin, and its ability to convey information depends on the reader being able to make out what is being depicted. But the term is not much favored by linguists, who prefer logogram, following I. J. Gelb. This is mainly a terminological difference, but true ideograms are signs that have no direct connection to words, while logograms do. Pictographs are now usually referred to as pictographs, rather than as ideograms.
There has been a persistent belief in the West that the Chinese characters are ideograms, but in fact the overwhelming majority of them (over 90%) have a phonetic basis. Facts, however, do not necessarily stop philosophers. Savants such as Leibniz declared that Chinese was a philosophical language, depicting pure thought in writing, and many others have amplified his claim. That is nonsense; no one who does not know Chinese can possibly read it through "pure thought". No one who does not know how to pronounce the characters (however badly) has ever learned to read them as a real language. But a part of the mystique of China in the modern West apparently derives from the sense that the writing system has mystical qualities.
Westerners, beginning with Diodorus Siculus, have also seen Egyptian hierglyphics as a mystical ideographic script. This erroneous view was given strength by the Neo-Platonist Plotinus (205-270) and by later works such as the Hierglyphika of Horapollo, which greatly influenced Marsilio Ficino and later Western mystics down to the present day. Unfortunately, it isn't true, either. Egyptian hierglyphics are mainly phonetic, with some logographic usage.
Ideographic usages occur prominently in Linear B, in Old Persian cuneiform, in Mayan, and in the so-called Indus script. Early Iranian texts display something called a heterogram: the use of an Aramaic word merely as a symbol to represent a totally different Iranian word. This phenomenon, which is like the use of kun-yomi in Japanese, has also been termed a type of ideography. But in truth there are no "ideographic languages" or wholly ideographic scripts. There are only cases where a script employs ideographic principles, usually in a small proportion of its total written forms.
The native Chinese tradition has special terminology for the different structural types of character, the so-called Six Scripts (liushu). There are a few modern scholars, notably Baron Peter Boodberg (1903-1972), who insist that all Chinese characters originally had a phonetic basis. That doesn't seem to be right, either, although research continues inexorably. | 
