Resolution of the 42nd CIPM (1948)
Adoption of "degree Celsius"
From three names (“degree centigrade”, “centesimal degree”, “degree Celsius”) proposed to denote the degree of temperature, the CIPM has chosen “degree Celsius” (PV, 21, 88).
reference
The reader should note that the official version of this Resolution is the French
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NOTE
This name is also adopted by the 9th CGPM (CR, 64).