Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dōnātĭo, ōnis, f. [dono], a presenting, a donation; in abstr. and concr. (for syn. cf.: donum, largitio, munus, donativum), Cic. Phil. 4, 4, 9; id. Verr. 2, 3, 80; id. Opt. Gen. 7, 19; id. Rosc. Am. 9; Just. Inst. 2, 7, de donationibus; the same title appears in Dig. 39, 5, and 6; Cod. Just. 5, 3; Vulg. Rom. 5, 17 al.; cf. Rein’s Privatr. p. 202 sq., and 340.