czar (n.)
1550s, from Russian tsar, from Old Slavic tsesari, from Gothic kaisar, from Greek kaisar, from Latin Caesar. First adopted by Russian emperor Ivan IV, 1547.
tsar (n.)
1660s, the more correct Latinization of Russian czar, from prehistoric Slavic *tsesar, from a Germanic source, ultimately from L. Caesar
Caesar:
c.1200, see caesarian; Old English had casere, which would have yielded modern *coser, but it was replaced in Middle English by keiser, from Norse or Low German, and later in Middle English by the French or Latin form of the name. Cæsar was used as a title of emperors down to Hadrian (138 C.E.), and also is the root of German Kaiser and Russian tsar (see czar). He competes as progenitor of words for "king" with Charlemagne (Latin Carolus), as in Lithuanian karalius, Polish krol. In U.S. slang c.1900, a sheriff was Great Seizer.
shah (n.)
title of the king of Persia, 1560s, shaw, from Persian shah, shortened from Old Persian xšayathiya "king," from Indo-Iranian *ksayati "he has power over, rules" from PIE *tke- "to gain control of, gain power over" (cf. Sanskrit ksatram "dominion;" Greek krasthai "to acquire, get," kektesthai "to possess"). His wife is a shahbanu (from banu "lady"); his son is a shahzadah (from zadah "son").
caesarian (n.)
1923, shortening of Caesarian section (1610s); supposedly from Caius Julius Caesar, who was said to have been delivered surgically, thus legend traces his cognomen to Latin caesus pp. of caedere "to cut" (see -cide). But if this is the etymology of the name, it was likely an ancestor who was so born (Caesar's mother lived to see his triumphs and such operations would have been fatal to the woman in ancient times). And Pliny derives his cognomen from caesaries "head of hair," since the future dictator was born with a full one. Caesarian section may come directly from caesus.