Well designed thesauri can represent semantic/conceptual knowledge so as to reveal relationships among different elements in documents, thus sewing as a critical tool in intelligent text retrieval systems and document analysis systems. In this paper, we present a thesaurus system, referred to as TheSys, which can be used as a tool for users to build thesauri according to their own requirements. It is our goal to design a comprehensive thesaurus building tool which can be used in any field of specialty rather than targeting for a partacular specialty field. People can use our system to build an electronic thesaurus in any specialty field required for a specific application. We propose Q thesaurus model, referred to as the thesaurus frame, which uses weighted links, to represent semantic relationships among concepts and terms. Our approach is to use a set of controlled terms, referred to as semantemes, to build the thesaurus frame. This approach can effectively reduce the size of the thesaurus yet the intelligence of the thesaurus is not compromised. 1169 0-8186-7128-9195 $4.00 0 1995 IEEE