Lewis & Short

ĕphippĭum, ii, n., = ἐφίππιον, a horse-cloth, caparison, housing (cf. clitellae): tegimen equi ad mollem vecturam paratum, Non. p. 108, 30 (pure Lat. stragulum); Varr. R. R. 2, 7, 15; id. ap. Non. l. l.; Caes. B. G. 4, 2, 4; Cic. Fin. 3, 4, 15; Gell. 5, 5, 3 al.
Prov.: optat ephippia bos piger, optat arare caballus, i. e. each envies the other’s condition, Hor. Ep. 1, 14, 43.