Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
dŏmĭnātor, ōris, m. [dominor], ruler, lord: rerum Deus, Cic. N. D. 2, 2, 4; Lact. 2, 14, 2; Vulg. Exod. 34, 6 al.