An information retrieval system including a plurality of indices representative of information stored in the information retrieval system and a dynamic lexicon is disclosed. The system includes memory having a database stored therein, the database being logically divided to include the plurality of indices, an information database having information objects stored therein and a dynamic lexicon which includes a plurality of data items and groups of data items that appear in the information database. A predetermined time variable represents the last time the plurality of indices were reindexed. After changes are made to the lexicon, a time stamp is attached to each one of the plurality of changes to the lexicon to indicate when the change was made to the lexicon. At some specified time interval later, the reindexing process is invoked. This process involves selecting a subset of the plurality of changes made to the lexicon after the predetermined time variable, locating all information objects in the information database that are affected by the plurality of changes to the lexicon, reindexing the portions of the plurality of indices representative of the information objects affected by the changes to the lexicon to reflect the changes in the lexicon, and then updating the predetermined time variable to indicate changes to the lexicon have been processed. The foregoing process is repeated until all changes to the lexicon after the predetermined time have been applied to the plurality of indices.