Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ănăbathrum, i. n., = ἀνάβαθρον, an elevated place for beholding public games: quae conducto pendent anabathra tigillo, tiers of benches that rest on hired beams, * Juv. 7, 46.