also: けんとう
noun
A literary, somewhat archaic term for winter, often used in poetry or elevated prose. Not used in everyday conversation; the common word is 冬 (ふゆ).
玄冬の候、皆様にはますますご清栄のこととお慶び申し上げます。
In this winter season, I hope you are all doing well.
この句は玄冬の厳しさを詠んだものだ。
This haiku captures the severity of winter.
The standard, everyday word for winter. 玄冬 is a literary, elevated synonym rarely used in modern speech.
From Chinese 玄冬 (xuándōng), where 玄 (dark, profound) and 冬 (winter) combine to poetically denote winter. The reading げんとう is the expected on'yomi; けんとう is a variant.