There are many advantages to be gained by storing the lexicon of a full text database in main memory. In this paper we describe how to use a compressed inverted file index to search such a lexicon for entries that match a pattern or partially specified term. This method provides an effective compromise between speed and space, running orders of magnitude faster than brute force search, but requiring less memory than other patternmatching data structures; indeed, in some cases requiring less memory than would be consumed by a single pointer to each string. The pattern search method is based on text indexing techniques and is a successful adaptation of inverted files to main memory databases.