the latin word is "sextus" "quintus" is the 5th, in ancient rome, your first name was just the sequence of your birth
Discussion
also, i'm not certain but i think that if you use the greek letter-numbers for 600, 60 and 6 that is the initials of the current chinese presidente, i forget what the word is but xi (ksi) is one of the old greek words for one of the numbers