late autumn; late fall
Refers to the latter part of autumn, typically around November in modern usage. Can be used as a noun or adverbially.
晩秋の山々は紅葉が美しい。
The mountains in late autumn are beautiful with autumn leaves.
晩秋になると朝晩は冷え込む。
In late autumn, mornings and evenings get chilly.
ninth month of the lunar calendar
Archaic use referring to the ninth month of the traditional lunar calendar, roughly corresponding to October in the modern calendar. See also 長月.
See also: 長月
旧暦では晩秋は長月にあたる。
In the old lunar calendar, 晩秋 corresponds to the month of 長月.
長月 is the traditional name for the ninth lunar month, synonymous with the archaic sense of 晩秋.
秋口 refers to the start of autumn, whereas 晩秋 refers to the tail end of the season, just before winter.
From 晩 (late) + 秋 (autumn). The archaic lunar calendar sense derives from the traditional Japanese month names.