Backset

noun

1. A setback or reversal.
2. An eddy or countercurrent in water.
3. To set upon in the rear.
4. To plow again, in the autumn, prairie-land which has been plowed for the first time in the preceding spring.
5. In lock-making, the horizontal distance between the front of the lock and the center of the keyhole: an essential measurement in lock-fitting.