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bissextile
Feb. 29th, 2016 08:07 ambissextile (bay-SEKS-til, bay-SEKS-tayl, bi-SEKS-til) - adj., of or pertaining to a leap year with an extra day. n., a leap year.
"With an extra day" because some lunar calendars have a leap month, but the word doesn't apply to them -- specifically, solar calendars, such as our current Gregorian and its predecessor Julian calendar, need to add an extra day roughly every four years to make the count of the earth's rotation match with its revolution. That would be today, now, but in the Julian calendar, it was inserted not at the end of February, but as a second 24th of Febraru, or rather as the Romans counted, extra sixth day before the calends (start) of March. So on leap years, there was a second sixth day, or bi(s)-sextus. (Why there? It's a holdover from the Julian's lunisolar predecessor, where a leap month was inserted after a February truncated to 24 days -- there's a reason Julius Caesar's calendar reform was needed.)
---L.
"With an extra day" because some lunar calendars have a leap month, but the word doesn't apply to them -- specifically, solar calendars, such as our current Gregorian and its predecessor Julian calendar, need to add an extra day roughly every four years to make the count of the earth's rotation match with its revolution. That would be today, now, but in the Julian calendar, it was inserted not at the end of February, but as a second 24th of Febraru, or rather as the Romans counted, extra sixth day before the calends (start) of March. So on leap years, there was a second sixth day, or bi(s)-sextus. (Why there? It's a holdover from the Julian's lunisolar predecessor, where a leap month was inserted after a February truncated to 24 days -- there's a reason Julius Caesar's calendar reform was needed.)
---L.
