intercolumnation
The distance, measured in diameters, between two columns. The types named by Vitruvius, with the ratios later assigned to them, are as follows: Pycnostyle, 1 1/2 D; Systyle, 2 D; Eustyle, 2 1/4 D; Diastyle, , 3 D; Araeostyle, 4 D. (Summerson, 1963)