At first glance, the variety of possible denotations of a given prefix in Russian might appear a chaotic set of idiomatic meanings, e.g. the prefix za- may refer to the beginning of an action, movement to a position behind an object, a brief deviation from a path, or completion of an action. I propose a unified analysis of Russian prefixes, where the differences in meaning are claimed to arise from different syntactic positions, while the lexical entry of a prefix remains the same. The main focus is on the verbs of motion due to the consistent duality displayed by the prefix meanings when added to directional and non-directional motion verbs. It turns out that prefixes modify path when added onto a directional motion verb and refer to movement in time with non-directional motion verbs. This semantic distinction corresponds to distinct sets of syntactic properties, characteristic of the lexical and superlexical prefixes. Furthermore, a tripartite division emerges in each set of prefixes, corresponding to goal, source and route of motion (TO, FROM, VIA, respectively) for lexical prefixes and to beginning, completion and duration for superlexical prefixes. This leads to the suggestion that the same prefix with a consistent conceptual meaning, shared with the corresponding preposition receives part of its denotation from its position in the syntactic representation. The separation of conceptual meaning from the structural meaning allows the polysemy to arise from position, rather than from arbitrary homophony. Thus, conceptual structure is unified with syntax.