porticus : POR-tih-cuss

(Latin; pl. porticus: porch). Long covered ambulatory with a roof carried on colonnades, sometimes attached to a building, and sometimes a separate structure. An open structure with a roof supported by columns. In a Roman theatre the covered colonnade at the rear of cavea or behind scene house. “Behind the scenes porticus are to be built; to which, in the case of sudden showers, the people may retreat from the theatre.” (Vitruvius).