Unit Definition (block [East U.S.])
The Block is an informal unit of distance popular in the U.S. A block is the average distance between street intersections in the rectangular street grids common in most American cities. The length of a block in Eastern USA is about 1/20 mile or 80 meters.

Unit Definition (pouce)
The pouce is a French "inch" unit, equal to 1/12 pied. Based on the pied de roi, the pouce equals about 1.066 inches or 2.707 centimeters. The word pouce means "thumb" in French.