Abstract. We propose to apply classical development methodologies to the design and implementation of Lexical Databases(LDB), which embody conceptual and linguistic knowledge. We represent the conceptual knowledge as an ontology, and the linguistic knowledge, which depends on each language, in lexicons. Our approach is based on a single language-independent ontology. Besides, we study some conceptual and linguistic requirements; in particular, meaning classifications in the ontology, focusing on taxonomies. We have followed a classical software development methodology for implementing lexical information systems in order to reach robust, maintainable, and integrateable relational databases (RDB) for storing the conceptual and linguistic knowledge. 1