noun
end of autumn; late autumn
Obsolete term. Refers to the final part of autumn, roughly corresponding to late October and November in the modern calendar.
季秋の候、ますますご清栄のこととお慶び申し上げます。
In this late autumn season, I hope you are doing well.
noun
ninth month of the lunar calendar
Refers specifically to the ninth month of the traditional Japanese lunar calendar, which roughly corresponds to October in the modern calendar. Used in historical or poetic contexts.
旧暦の季秋は、今の十月にあたる。
The ninth month of the old lunar calendar corresponds to modern October.