红火
hóng huǒ · HSK 7
prosperous
🔴🔥 红火 = red + fire; a business so hot and red it is booming and prosperous
红 (red) + 火 (fire). Red is the lucky, festive color and fire means hot or flourishing, so together they describe something thriving, booming, and prosperous.
红 — silk radical 糹/纟 + work 工 (phonetic)
红 is a semantic-phonetic compound. The silk radical 糹 (simplified 纟) signals the meaning, since the character originally referred to a kind of pink or light-red dyed silk. The right side 工 supplies the sound. Over time the meaning broadened from the dye color to 'red' in general.
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.