Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pĭrus, i, f., a pear-tree: insere nunc, Meliboee, piros, Verg. E. 1, 74; Plin. 16, 24, 38, § 90; 16, 26, 46, § 109; 16, 25, 42, § 103: felix arbor, Macr. S. 3, 20, 2.