winter; wintertime; winter term
Refers to the winter season or period, often used in formal or scheduling contexts (e.g., 冬期講習, 冬期休暇). Can function as a noun or adverbially.
冬期はスキー場がにぎわう。
The ski resort is busy during the winter season.
I signed up for the winter term course.
I decided to take a winter course at a cram school.
During the winter period, business hours become shorter.