The degree celsius is a unit of temperature named for the Swedish astronomer, Anders Celsius (1701-1744), who first proposed it in 1742. With respect to the Celsius temperature scale, the freezing point of water is 0 degrees, and the boiling point is 100 degrees. Hence a degree celsius has the same size as a degree kelvin.
Anders Celsius originally proposed that the freezing point should be 100 degrees and that the boiling point should be 0 degrees however this was reversed, possibly at the instigation of Carl von Linne, otherwise known as Linnaeus, or possibly at the instigation of Daniel Ekstrom, the manufacturer of most of the thermometers used by Celsius.
The Celsius scale is used in most of the world for day-to-day purposes. It was formerly called the centigrade scale.