The main aim of my paper is to describe the cognitive semantic research focusing on the preverb be 'in'. The dialectical words, which are the corpus of my investigation were collected by the linguist Ferenc Sima. The preverb be 'in' is one of the most productive categories in this corpus – it is present 56 times in root position. Since the meaning could be described as conceptual structures due to the categorization in cognitive domains and profiling, the preverb + verb (igekötős ige) structure utilising the prototype principle is analysed in my work. Departing from the directional meaning of be as in bemegy 'in + go', the rest of the functions of that preverb can be derived, and the necessary categories and subcategories can largely be drawn up. The delineation of the semantic structure is based on Langacker's theory and methodology, which define the preverb + verb as a composite structure (Langacker 1987, 2008).