Definitions are the privileged medium for providing users with a representation of the meaning of a lexical unit. Even if many resources contain very rich semantic and/or conceptual information, definitions are still extremely useful and help users to fully grasp the meaning of lexical units or concepts.

The research that will be presented is part of a larger project on the semi-automatic generation of definitions of semantically-related terms in specialized resources. This presentation will focus on the formulation of instructions to generate the definitions of sets of morphologically-related predicative terms, based on the definition of one of the members of the set. In many cases, it is assumed that the definition of a predicative term can be inferred by combining the definition of a related lexical unit with the information provided by the semantic relation (i.e. lexical function) that links them. In other words, terminographers only need to know the definition of pollute and the semantic relation that links it to other morphologically-related terms (polluter, polluting, pollutant, etc.) in order to create the definitions of the set. The results show that rules can be used to generate a preliminary set of definitions (based on specific lexical functions). They also show that more complex rules would need to be devised for other morphological pairs.