Compound term processing is the name that is used for a category of techniques in Information retrieval applications that performs matching on the basis of compound terms. Compound terms are search terms that contain more than one word, for example "triple" is a single word term but "triple heart bypass" is a compound term.
In August 2003 Concept Searching Limited introduced the idea of using Compound term processing via an article published in INFORMATION MANAGEMENT AND TECHNOLOGY (VOL 36 PART 4). A British Library Direct catalogue entry can be found here: [1].
The complete original article can also be downloaded from here: [2].
Compound term processing is important because if allows search (and other Information Retrieval) applications to perform their matching on the basis of multi-word concepts rather than single words in isolation which can be highly ambiguous.
Techniques for probabilistic weighting of single word terms dates back to at least 1976 and the landmark publication by Stephen Robertson and Karen Spärck Jones: Relevance weighting of search terms originally published in the Journal of the American Society for Information Science. [3] Professor Stephen Robertson has stated repeatedly that the assumption of word independence is “patently not justified” and exists simply as a “matter of mathematical convenience”.
In 2004 Anna Lynn Patterson filed a number of patents on the subject of "Phrase based indexing and retrieval" and to which Google subsequently acquired the rights. A full discussion of the patents can be found here: Webmaster Woman. The patents themselves can be found online, for example: [4].