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Instead of sleeping I was wondering about cardinal and ordinal numbers. Why do cardinal numbers share a name with a red bird we mostly don't get in California? The bird is named after the office in the Catholic Church, whose holders dress all in red (like Cardinal Richelieu, or Michael Palin in the Spanish Inquisition sketch). Cardinals wear read because of their willingness to shed their blood in defense of the Church; or else as a symbol of the blood of Christ; or else because the Romans placed a scarlet robe on Jesus when he was about to be executed (scarlet according to Matthew but purple according to several other gospels); or, originally, just to distinguish them from lesser priests. The word "cardinal" derives from the Latin for "hinge-like", and basically means "central" or "important", like when something hinges on something else. The cardinal numbers are just "the numbers", one, two, three, etc. They're the important central ones.

Ordinal numbers express order, first second third etc. The etymology is fairly obvious. But why do we use ordinal numbers for fractions (kinda mostly, except for first and second and fourth vs whole and half and quarter)? It turns out a lot of languages, and almost all Romance languages, do the same. "A third" comes from "a third part", but why is THAT ordinal? The best explanation I could find from 10 minutes of googling was that you cut the thing into three parts and then take the last one, that's a third part. Seems fishy. But, that's etymology for you.