Lewis & Short

Astrăba, ae, f., = ἀστράβη, a wooden saddle, a sumpter-saddle; the title of a lost comedy attributed to Plautus; its authenticity was suspected even in ancient times; v. Gell. 11, 7; Non. p. 70; Paul. ex Fest. s. v. subscudes, p. 306 Müll.