In their pivotal work Convergentie en divergentie in de Nederlandse woordenschat: Een onderzoek naar kleding- en voetbaltermen Geeraerts, Grondelaers & Speelman (1999) introduce the notion of profile-based measures of lexical variation. The adopted profile-based perspective takes its starting point in the onomasiological profile of a concept, i.e. the synonyms with which the concept may be lexicalised, distinguished by their relative frequencies. The uniformity measure derived from these profiles calculates the degree of overlap between two language varieties. Two additional measures complete the picture: the internal uniformity measure allows to quantify the homogeneity of concepts, and the proportion measure calculates the proportion of terms with a specific feature (e.g. foreign origin). In Geeraerts, Grondelaers & Speelman (1999) these three measures are used to investigate how the Dutch lexicon in Belgium and that in the Netherlands relate to one another and how they develop. In this dissertation, we step up from the original research goal set out by Geeraerts, Grondelaers & Speelman (1999). By introducing three new lexical fields, each with its own characteristics, we raise new research questions, and develop the representativeness of the study. Through four case studies we aim to elaborate upon the three profile-based measures of lexical variation introduced above. The first case study replicates the clothing terminology case study from Geeraerts, Grondelaers & Speelman (1999) and adds a new temporal measuring point to track the evolution of the data up to Present-Day Dutch. In the second case study the focus shifts towards (lexical) language norms in traffic terminology and towards how they influence the degree of uniformity. We will consider a number of different language policy planning sources such as prescriptive reference works, governmental nomenclature and exo-/endogenousness. For the third case study, we zoom in on anglicisms in the field of IT and study which factors determine their success. For instance, we will look into the effect of word length, source language frequency and morphological composition. We will also verify whether the success of anglicisms within a concept influences the degree of uniformity. The fourth case study is concerned with the internal structure of emotion concepts. Which concepts are typically lexicalised by one preferred term and for which concepts many alternative synonyms compete? How does this relate to the degree of uniformity of these concepts? In addition to the onomasiological profile-based approach to lexical variation in Dutch, we explore for each of the three new lexical fields different semasiological prospects since the two perspectives are closely intertwined (Geeraerts, Grondelaers & Bakema 1994). References Geeraerts, Dirk, Stefan Grondelaers & Dirk Speelman. 1999. Convergentie en divergentie in de Nederlandse woordenschat: een onderzoek naar kleding- en voetbaltermen. Amsterdam: P.J. Meertens-Instituut Geeraerts, Dirk, Stefan Grondelaers & Peter Bakema. 1994. The Structure of Lexical Variation. Meaning, Naming, and Context. (Cognitive Linguistics Research [CLR] 5). Berlin/New York: Mouton de Gruyter.