When Sir Patrick Geddes, a Scottish biologist turned sociologist, sat down in 1915 to write Cities in Evolution, a work on urban planning, he needed a word. How should he refer to thickly populated regions consisting of a sprawling range of cities clustered together? "Some name, then, for these city-regions, these town aggregates, is wanted…. What of 'conurbations'?" he asked rhetorically early on in his work. For his coinage, Geddes combined urbs (the Latin word for "city," already familiar in urban and suburb) with the Latin prefix con- ("together") and the English noun suffix -ation. It turned out that his word suited English speakers just fine-we've been using it ever since.