nōn

Nōn in Old English comes from Latin nona hora — the ninth hour. The Romans divided daylight into twelve hours beginning at sunrise, approximately 6 a.m. The ninth hour was approximately 3 p.m. Early Christian monasteries adopted Roman time-keeping, and the canonical hour of None — the prayer service at the ninth hour — was set at 3 p.m.

Between the twelfth and fourteenth centuries, the time of the noon meal shifted. Monks, who fasted until the None service, gradually moved that service earlier — from 3 p.m. to 2 p.m. to 1 p.m. to, eventually, 12 p.m. The meal that followed the service moved with it. By the fourteenth century, 'noon' meant 12 p.m. in English. The ninth hour became the sixth hour. The word did not change. The clock did.

This shift is one of the best-documented examples of a word changing its referent without changing its form. 'Noon' still sounds like it always sounded. It still seems like it means what it always meant. But it moved three hours in two centuries because hungry monks bent the rules. The linguistic drift was driven by appetite.

Modern English has no memory of the ninth hour. 'High noon' means 12 p.m. exactly — a western-movie showdown at the sun's peak. The word is completely detached from its Latin arithmetic. None of the original math remains: ninth hour, ninth hour of what, counting from when. The word just means the middle of the day now. It forgot how it got there.