Celsius temperature scale (sĕlˈsēəs) [key], temperature scale according to which the temperature difference between the reference temperatures of the freezing and boiling points of water is divided into 100 degrees. The freezing point is taken as 0 degrees Celsius and the boiling point as 100 degrees Celsius. The Celsius scale is widely known as the centigrade scale because it is divided into 100 degrees. It is named for the Swedish astronomer Anders Celsius, who established the scale in 1742. William Thomson Kelvin used it as the basis of his absolute temperature scale, now known as the Kelvin temperature scale, in 1848 (see also absolute zero). Temperatures on the Celsius scale can be converted to equivalent temperatures on the Fahrenheit temperature scale by multiplying the Celsius temperature by 9/5 and adding 32° to the result, according to the formula 9 C /5+32 = F.