SHAH, the title of the kings of Persia, the full title being padshah, i.e. " lord king," Pers. pati, lord, and shah, king (see PADISHAH, the Turkish form of the word). The word shah is a much shortened form of the O. Pers. khsayathiya, probably formed from khsayathi, might, power, khsi, to rule. The Sanskrit kshatram, dominion, is allied, cf. also " satrap." From the Pers. shah mat, the king is dead, is ultimately derived, through the Arab, pronunciation shag, " check-mate," then " check," " chess," " exchequer," etc.
Note - this article incorporates content from Encyclopaedia Britannica, Eleventh Edition, (1910-1911)