Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

arbī̆trātor, ōris, m. [arbitror], in late Lat. = arbiter, II. B., a master, ruler, lord: JVPPITER ARBITRATOR, Inscr. Gud. 7, 5.
Hence a place in the tenth district at Rome is called Pentapylon Jovis arbitratoris, Publ. Victor. Reg. 10.