EcoLexicon, a multilingual knowledge resource on the environment, provides an internally coherent information system covering a wide range of specialized linguistic and conceptual needs. Data in our terminological knowledge base (TKB) are primarily hosted in a relational database which is now linked to an ontology in order to apply reasoning techniques and enhance user queries. The advantages of ontological reasoning can only be obtained if conceptual description is based on systematic criteria and a wide inventory of non-hierarchical relations, which confer dynamism to knowledge representation. Thus, our research has mainly focused on conceptual modelling and providing a user-friendly multimodal interface. The dynamic interface, which combines conceptual (networks and definitions), linguistic (contexts, concordances) and graphical information offers users the freedom to surf it according to their needs. Furthermore, dynamism is also present at the representational level. Contextual constraints have been applied to reconceptualise versatile concepts that cause a great deal of information overload.