1) Unit of plane angle 
The gradian is a unit of plane angle, equivalent to {frac|1|400} of a turn. It is also known as gon, grad, or grade. One grad equals {frac|9|10} of a degree or {frac|{{pi}|200}} of a radian. In continental Europe, the French term centigrade was in use for one hundredth of a grad, and the term myriograde was in use for one ten-thousandth of a grad....