Spatial variation of language has been researched qualitatively and quantitatively for at least 150 years by different sub-disciplines of linguistics, each defining differently what dialects and dialect areas are. Linguists agree, however, that the concept of dialect is vague and the extent of a dialect is fuzzy. With contact being a crucial driver of linguistic change at sub-language levels, we attempt to sketch the perspective that contact dialectology and related sub-disciplines can offer on this fuzziness with regard to the spatial variation of dialects and dialect areas. Thus we address contact processes and patterns characterizing individuals, groups, com munities, areas and beyond, at temporal scales spanning from mundane contact through generations to deeper time enough for dialects to diverge and disappear.