Exhaustion
EXHAUST'ION, noun The act of drawing out or draining off; the act of emptying completely of the contents.
1. The state of being exhausted or emptied; the state of being deprived of strength or spirits.
2. In mathematics, a method of proving the equality of two magnitudes by a reductio ad absurdum, or showing that if one is supposed either greater or less than the other, there will arise a contradiction.