What Is the Difference Between Celsius and Centigrade?
The difference between Celsius and centigrade lies in the 0.01 degree variation that exists between the triple point of water in each scale. The Celsius scale replaced the centigrade scale established in 1741 by Anders Celsius.
Aside from that small difference, the two scales are basically the same. Zero degrees is the point at which water freezes and 100 degrees is the temperature at which water boils in both systems. Because the centigrade system did not have a precise value for the degree, the General Conference of Weights and Measures decided to develop the Celsius scale, which is the Kelvin scale minus 273.15 degrees. Because the triple point of water (the equilibrium point for ice, liquid and vapor) in the Kelvin scale is 273.16, the same point is 0.01 in the Celsius scale.