Etymology
From Latin nōnus (“ninth”).
As a day of the Roman calendar, via nōnae (“ninth days”) from the original Roman practice of counting forward to the next full or new crescent moon, the nones' occurrence 8 days before the ides of every month (9 counting inclusively) following the establishment of a fixed calendar, and from the Latin practice of treating most recurring calendrical days as plurals. Some scholars believe the name is a variant of the nundines (nūndinae fēriae (“ninth-day festival”)), the Roman market days held every eight days (9 counting inclusively), which were likely announced for each coming month by the Roman kings on the first-quarter days.
As a time of day, via the plural form of Middle English, Anglo-Norman, & French none and Latin nōna (“ninth hour”) after the manner of ea