LSJ
οἱ, (< αἴθω) the Persian fire-worshippers, Str. 15.3.15; hence πυραιθεῖον, τό, their temple, ibid.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)
Pape
οἱ, die Feueranbeter Persiens, Strsb.
Pape, Griechisch-deutsches Handwörterbuch (3. Aufl., 1914)