Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† orthĭus, a, um, adj., = ὄρθιος, high, lofty (post-class.): carmen quod orthium dicitur (Gr. νόμος ὄρθιος), Gell. 16, 19, 14: orthius (pes), qui ex tetrasemi elatione, id est arsi, et octasemi positione constabit: ita ut duodecim tempora hic pes recepisse videatur, Mart. Cap. 9, § 985.