In Languages for Specific Purposes (LSPs), variation and term formation are often seen as related phenomena, variation being interpreted as a sign of neology. In scientific discourse though, variation can play specific roles, thereby giving a different dimension to neology as a linguistic process than generally implied in terminological studies. The well-known referential function, consisting of creating new designations for naming new concepts, can be set aside in scientific texts to create space for what we define as the cognitive function: a situation where a scientist purposefully employs term variation as a means for theorising and better explaining a given concept. We argue that Halliday's "grammatical metaphor" and "given-new" information theory provide an interesting background for understanding scientific term formation processes, and the ensuing issue of terminological variation. Consequently, in this article, we try to place the phenomenon of neology and of terminological variation within the framework of discourse analysis, by devising a method for probing sequential behaviour of terminological variants across text sections. Additionally, this study aims to improve building lexical resources within the ARTES terminological and phraseological multilingual database project, which serves as a support for developing lexicographical and translational skills in students in specialised translation.