Medical Terminologies play a vital role in clinical data capture, reporting, information integration, indexing and retrieval. The Web Ontology language (OWL) provides an opportunity for the medical community to leverage the capabilities of OWL semantics and tools to build formal, sound and consistent medical terminologies, and to provide a standard web accessible medium for inter-operability,access and reuse. One of the tasks facing the medical community today is to represent the extensive terminology content that already exists into this new medium. This paper addresses one aspect of this challenge - how to incorporate multilingual, structured lexical information such as definitions, synonyms, usage notes, etc. into the OWL ontology model in a standardized, consistent and useful fashion.