Definition: degrees Celsius.
Example: Today it is 3 centigrade.
Rarity: bottom 40% of words in common usage (Merriam-Webster).
Etymology: 1799, from French: centi- (one hundred) + grade (degree of measurement; via Latin gradus “step, pace, gait”). [http://www.etymonline.com/]
Word in Use: “Designed to function in temperatures ranging from minus 32 to 49 centigrade, the Centauro II engine provides 24 horsepower per ton compared to 19 for the old Centauro. ” (http://www.defensenews.com/articles/italys-new-centauro-ii-tank-shown-off-in-rome)
Across languages: Spanish: centigrados; in use: “Termometro descendio hasta 6 grados centigrados en SLP.” (http://pulsoslp.com.mx/2016/10/20/termometro-descendio-hasta-6-grados-centigrados-en-slp/ )
Why I like this word: I like the word centigrade because it has a certain economy to it; it allows one to skip saying “degrees Celsius,” while still being correct (saying simple Celsius is incorrect, it must be degrees Celsius). It also has a rather nice Latinate quality to it. In Spanish one loses the economy, having to say grados centigrados; however, that too has a rather pleasant continuity to it.