Pi (π)
Mathematical constant representing the ratio of a circle's circumference to its diameter.
Mathematical/Western · 1706 – present
Degree Celsius (°C)
Unit symbol for temperature in the Celsius scale.
Description
The degree Celsius (°C) is the unit of temperature in the Celsius scale, named after Swedish astronomer Anders Celsius who proposed a similar scale in 1742. In the Celsius scale, 0°C is defined as the freezing point of water and 100°C as the boiling point at standard atmospheric pressure. The Celsius scale is used worldwide for everyday temperature measurement and in most scientific contexts (with the Kelvin scale used for absolute temperatures). The symbol °C is standardized by the International System of Units (SI) and ISO 80000-5.
Origin & Cultural Context
The Celsius scale was proposed by Anders Celsius in 1742. The degree symbol (°) combined with C was standardized by the SI system.