Lewis & Short

ĕpistȳlĭum, ii, n., = ἐπιστύλιον, in arch., the cross-beam that rests on the columns, the architrave, Vitr. 3, 1 sq.; 4, 3; 5, 1; Varr. R. R. 3, 5, 11; Plin. 36, 14, 21, § 96; cf. Paul. ex Fest. p. 82, 11 Müll. Isid. Orig. 15, 8, 15; 19, 10, 24; Vulg. 3 Reg. 7, 6 al.