Abstract: A dictionary system available for the use in document search or available for the use in normalization of a term constituting a document. A dictionary system capable of supporting a complex term composed of a plurality of simple terms. A dictionary system includes a storage for storing a simple term dictionary unit containing at least one simple term and a complex term dictionary unit which represents a complex term that contains one of the simple terms constituting the simple term dictionary unit. Each simple term constituting the complex term is referred to through a pointer (unit identifier) to the simple term dictionary unit.