adj \ˈsel-sē-əs, -shəs\

Definition of CELSIUS

: relating to or having a scale for measuring temperature on which the interval between the triple point and the boiling point of water is divided into 99.99 degrees with 0.01° being the triple point and 100.00° the boiling point—abbreviation Celsius; compare centigrade

Biographical Note for CELSIUS

Celsius, Anders (1701–1744), Swedish astronomer. Celsius's major contribution was his thermometer scale. Although not the first thermometer with a 100-degree scale, his scale, described in 1742, used the freezing and boiling points of water as its two fixed points, with 0° for the boiling point and 100° for the freezing point. Five years later the system was reversed so that 0° represented the freezing point and 100° represented the boiling point and then it gradually gained acceptance. Since about 1800 Celsius has been used as an adjective to designate a thermometer based on the revised scale and more recently to indicate the scale itself.

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