Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† pĕpo, ŏnis, m., = πέπων, ονος, a species of large melon, a pumpkin, Plin. 19, 5, 23, § 65; 20, 2, 6, § 11; Tert. Anim. 32; id. adv. Marc. 4, 40; Vulg. Num. 11, 5.