Automatic text analysis systems can lexically recognize a word only if it already exists in the electronic dictionary. The same thing is true for the NOOJ system analysis programs. One understands here by electronic dictionaries the lexical databases where all information is explicit because they are intended for computer programs use. These bases aim at the modelling of the language, which distinguishes them from the electronic lexicons created for particular applications needs. For technical languages or of speciality, work remains to be made to build dictionaries. Our work applies to the NOOJ system, with for immediate objective the installation of an electronic dictionary of French computer science terms (compound words), with an aim of analysing, automatically indexing texts. The linguistic aspects of the terminology are retained.