Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prūnum, i, n. [prunus], a plum: cerea, Verg. E. 2, 53: cereola, Col. 10, 404; 12, 10, 2; Plin. 15, 13, 13, § 44: spini jam pruna ferentes, Verg. G. 4, 145; Ov. M. 13, 817; Mart. 13, 29, 1.