Within the scientific field of translation studies, the conceptual boundaries of translation and related notions (e.g. localisation, transcreation) have been much discussed in recent years. Rather than attempting to settle the scholarly debate, however, this chapter zooms in on translation professionals and studies how they understand and use the concepts of their trade in practice. Specifically, it reports on a study that investigates how practitioners at a large UK-based translation company perceive translation and related concepts. Concepts addressed include translation, interpreting, subtitling and dubbing, localisation, transcreation, and adaptation, as well as intralingual and intersemiotic translation. Methodologically, the study draws on focus groups with staff translators and project managers complemented by an individual interview with the managing director of the translation company. The data and findings of the study are analysed and explained with recourse to prototype theory, and results are discussed in relation to current conceptualisations and boundary discussions in translation studies.