Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ĕpĭrēdĭum, ii, n. [ἐπί-reda; perh. derived immediately from the Greeks, who adopted the Gallic reda into their language], a thong by which a horse was attached to a cart, Juv. 8, 66; Quint. 1, 5, 68.