烟
yān · HSK 3
smoke
💨 火 (fire) + 因 (cause) — fire-caused vapor
烟 decomposes into 火 fire and 因 cause/reason — what fire causes is smoke. The right side 因 also hints at the sound yīn, close to yān.
烟 — fire radical 火 + 因 (cause, phonetic)
A semantic-phonetic compound: 火 ('fire') gives the meaning, while 因 supplies the sound 'yīn', close to 'yān'. Originally referring to the smoke rising from a fire, 烟 later extended to mist, vapor, and eventually tobacco and cigarettes in modern usage.