Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† hippodrŏmos, i, m., = ἱππόδρομος, a race-course for horses, hippodrome, Plaut. Bacch. 3, 3, 27; Plin. Ep. 5, 6, 19; Mart. 12, 50, 5; Sid. Ap. 2, 2.