Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mistĭo (mix-), ōnis, f. [misceo], a mixing (post-Aug.): aliam mixtionem habet genus avium, Vitr. 1, 4, 7; plur., id. 1, 4, 6; 11.
Transf., concr., a mixture, Pall. 1, 34, 5; 12, 7, 1.
mixtārĭus, mixtĭo, etc., v. mist-.