An Etymological Dictionary of Astronomy and Astrophysics

The official name of the centigrade temperature scale with the → ice point as 0° and the → boiling point of water as 100°. The Celsius scale uses a degree (the unit of temperature) which has the same magnitude as the degree on the → Kelvin scale:
T_C = T_K - 273.15. See also → Fahrenheit scale, → Rankine scale, → Reaumur scale.

See also: In honor of Anders Celsius (1701-1744), Swedish astronomer, originator of the first centigrade temperature scale. However, in his original scale Celsius had 100° for the ice point and 0° for the steam point; → scale.