The study of terms and terminologies and the study of technical translation and translations enjoy a symbiotic relationship. Terms make an important semantic contribution to lexically dense texts dealing with specialist subject matter, and hence to their translation. On the one hand, data on terms and their equivalents, e.g. in technical dictionaries or termbases, support technical translators in their decision-making. On the other hand, the compilation of codified lexical resources increasingly draws on texts, including translations, as a basic data source. Codified lexical resources and texts (original or translated) are, however, organisms of different kinds. Translation competence therefore includes knowledge of how to navigate the path between these symbiotic organisms in a bi-directional way: firstly in using codified resources to solve terminological problems when interpreting a given source text and then creating a new text in the form of a translation, and secondly in using texts as a source of data for compiling, for example, personal glossaries or providing feedback to a terminology manager to extend or update existing resources. This paper discusses the key notion of equivalence from a terminological point of view that is rooted in textual analysis. [Source: A. Matthyssen]