Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mūseiārĭus and mūsaeārĭus, ii, m., for musivarius, a worker in mosaic (post-class.): marmorarius, musaearius, albarius, Edit. Diocl. p. 19; Inscr. Grut. 586, 3.