Introduction. The systems here presented are both conceived as Computer Dictionary Systems for human use. IDHS supports reasoning mechanisms analogous to those used by humans when consulting a monolingual dictionary. MLDS has been thought as an online computational help system for human translators. The starting point of IDHS is a Dictionary Database (DDB) built from an ordinary monolingual (explanatory) French dictionary. Meaning definitions have been analysed using linguistic information from the DDB itself and interpreted in order to be structured as a Dictionary Knowledge Base (DKB). The intelligent exploitation of the dictionary is supported by the resulting DKB, that is based on the representation of the dictionary as a semantic network of frames, where each frame represents one concept. Frames are interrelated by attributes representing lexical-semantic relations such as taxonomy, synonymy, meronymy, and specific relations derived from the lexicographic metalanguage use