எத்தனாவது

One of the English language's omissions is a question word for identification of a specific number in a sequence. In Tamil this is எத்தனாவது (ethanaavathu), which-eth. Which-eth is not too bad if you are around people who have studied Mathematics, but otherwise you just sound rather silly. Which-index is just as bad but works with programmers.

The English constructions seem awkward, though they are fairly concise, "Which number President is Barack Obama?" sounds strange. If you want to know which parking spot by number, you might say "What number was the parking spot?" since they are naturally ordered, but if you were to say "Which President was Barack Obama?" answers wouldn't naturally point to the number.