1) An awning found in a theater 2) Ancient Roman architecture 1) Awning 
awning over an auditorium
• (n.) The marginal membrane of certain medusae belonging to the Discophora.
A vast cloth awning, which could be dragged and stretched over an open-air theatre or amphitheatre using a system of ropes and pulleys. It was designed to shield the spectators from the sun. 
Ve·la'ri·um noun ; plural Velaria . [ Latin , a covering.] (Zoology) The marginal membrane of certain medusæ belonging to the Discophora. 
velarium In ancient Rome, a large awning (covering) used in amphitheaters to shade the audience.
(Latin) an awning found in a theater.
(Latin; pl. velaria). An awning in a Roman theatre or amphitheater that stretched above the audience as protection from the sun and elements. Also referred to as velum.