Where does “Pi Day” come from?

Pi Day (English) comes from English Day, from Middle English day, from Old English dæġ, from Proto-West Germanic dag, from Proto-Germanic dagaz, from Proto-Indo-European dʰegʷʰ- — to burn; warm, hot.

Pi Day (English): March 14th, an annual celebration of the mathematical constant π (pi)

Definitions

  1. March 14th, an annual celebration of the mathematical constant π (pi)

Ancestry of “Pi Day”, step by step

Pi Day traces back through two separate lines of ancestry.

via English Day

StepLanguageWordMeaning
1EnglishDayderived from a medieval diminutive of David
2Middle Englishdayday; daylight, sunlight; epoch, age, period
3Old Englishdæġday, daytime
4Proto-West Germanicdagday
5Proto-Germanicdagazday; name of the D-rune
6Proto-Indo-Europeandʰegʷʰ-to burn; warm, hot

via English Pi

StepLanguageWordMeaning
1EnglishPiThe sixteenth letter of the Classical and Modern Greek alphabets and the seventeenth in Old Greek
2Ancient GreekπῖAlternative form of πεῖ
3Ancient Greekπεῖpi, the name for the sixteenth letter Π, π of the...
4Proto-Semiticpay-the mouth
Every word from Proto-Indo-European dʰegʷʰ- →