Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
prūna [root in Gr. πῦρ, fire], ae, f., a burning coal, live coal (cf. carbo): medium per ignem multā premimus vestigia prunā, Verg. A. 11, 788 Serv.; 5, 103: latum clavum prunaeque batillum, Hor. S. 1, 5, 36; Plin. 20, 6, 23, § 54; 29, 3, 11, § 45 al.