Heterogram (from [Greek] heteros, meaning "different", + -gram, meaning "written") is a term used mostly in the study of ancient texts (philology), referring to a special kind of a logogram consisting of the written representation of a word in a foreign language. In most cases, the two languages share the same script. However, while the word in the foreign language may be written either phonetically (representing the sounds of the foreign language) or logographically, in the borrowing language it is necessarily a logograph, since there is no relationship between the symbols used and the pronunciation of the word in the borrowing language.
For example, in English the abbreviations e.g., i.e., and viz. can be read as "for example", "that is", and "namely". When read this way, they may be considered abbreviated heterograms, since they stand for the Latin exempli gratia, id est, and videlicet. (They can also be read as spelled, /iː dʒiː/ ee gee and so on.)
Heterograms are frequent in cuneiform scripts, such as the writing of Akkadian, which uses Sumerian heterograms. In Middle Iranian scripts derived from the Aramaic scripts (such as the Pahlavi scripts), all logograms are heterograms coming from Aramaic. Sometimes such heterograms are referred to by terms identifying the source language such as "Sumerograms" or "Aramaeograms".