冬天
dōng tiān · HSK 2
winter
❄️ 冬天 = winter (冬) + sky/day (天); the season-sky compound
冬 alone means winter; pairing it with 天 (sky/day) gives the everyday word for the winter season, much like 春天 spring, 夏天 summer, 秋天 autumn all take 天 as a suffix.
天 — 一 (one/sky) above 大 (big person)
Originally a pictograph of a person (大) with an emphasized head, representing what is above — the sky or heavens. The top stroke evolved into 一, symbolizing the vast expanse overhead. From 'sky' it extended to mean 'day,' 'heaven,' and 'nature.'