The project is concerned with three related issues in contemporary semantics: the role of space in the semantic organisation of language, domain-neutral properties of linguistic meaning, and the hierarchical structure of semantic systems. It investigates these issues through synchronic and diachronic studies of Swedish, with a special focus on prepositions. Within the synchronic study of meaning, a major goal is to develop and refine a theory of semantics that facilitates precise descriptions of linguistic meaning in an hierarchical and domain-neutral fashion. From the diachronic perspective, the project investigates the hypothesis that there are two, partly opposing diachronic processes at work in many semantic changes: one process of innovative change that involves extension from spatial meaning to non-spatial meaning, and another process of reductive change, in which spatial meanings are lost.