The present study focuses on functions and English translation counterparts of the Czech lexeme aby. It is a relatively frequent word in the Czech language which is described as a subordinating conjunction expressing purpose, effect, manner, and also as a particle with a number of discourse functions. The current description, however, does not seem complete and this study therefore aims to analyse its use in more detail. Lexicographic and grammatical sources served as a basis for the classification of aby as a conjunction and as a particle. However, it became evident soon after the initial analysis that this listing is not complete and the use of aby is more complex than originally expected. The present paper thus treats all the functions of aby and also exemplifies each of them using extracted corpus data. In the study, aby in its conjunction and particle use is firstly treated separately to analyse each of them in more depth. This analysis, consequently, provides basis to point out their common features as well as their differences. The English translational counterparts are another point of interest in the study, in particular, their adequacy, regularity, and lexicalization.