焰火
yàn huǒ · HSK 7
firework
🎆 焰 (flame) + 火 (fire) = fireworks, the festival kind that blaze in the sky
焰 means flame and 火 means fire, so 焰火 stacks flame-on-fire for the burst of a firework. Compare 烟火 (yān huǒ), same fireworks sense but led by 烟 smoke instead.
火 — pictograph of flames rising
火 is a pictograph showing flames rising upward from a fire, with the central stroke as the main blaze and the side strokes as sparks. The ancient oracle bone form looked even more clearly like a burning flame. It still means 'fire' today and serves as a common radical in characters related to heat, burning, or cooking.