Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
fornācātor (FVRNACATOR in an inscr. found at Pompeii, v. Rosin. Dissert. Isag. p. 66, tab. 10, no. 2), ōris, m. [fornax], the heater of a bath-furnace, a bath-heater, Dig. 33, 7, 14.