pĕristȳlum, i, n., = περίστυλον,
the part of a building enclosing the court-yard , surrounded by columns on the inside , Varr. R. R. 3, 5; Cic. Dom. 44, 116; Suet. Aug. 82; Aus. Urb. 5.
peristȳlum ī, n , περίστυλον, an open court surrounded by a colonnade, peristyle. ...
An Elementary Latin Dictionary