Celsius

Part of speech: noun

Definitions

1. A system for quantifying temperature based on two reference points, namely the freezing and boiling points of water under normal atmospheric conditions
2. A method for measuring thermal energy, relying on the defined points where water freezes and boils at standard pressure
3. A scale to measure heat where zero marks water freezing and one hundred marks boiling under standard conditions

Etymology: Anders Celsius, a Swedish astronomer, proposed his temperature scale in 1742, and the name he is remembered by was itself a Latinized version of his family's estate name. His surname came from the estate, which took its name from the Latin "celsus", meaning "mound" or "elevated". Latinizing family names was a common scholarly habit in Sweden at the time, so the astronomer's name carried a hint of a hill. The scale he devised was originally called the centigrade scale, from Latin roots meaning "hundred steps", because it divided the interval between the freezing and boiling points of water into one hundred degrees. Celsius's original arrangement was reversed: he set boiling at zero and freezing at one hundred. Later scientists flipped the scale to its familiar orientation, and the unit eventually took his name, so the word "celsius" now honours him rather than describing the number of divisions.