蒸発
じょうはつ · jouhatsu · JLPT N2 · noun
vaporization
💧 蒸 = steam + 発 = send out: steam sent off into the air, so the thing is gone
Both meanings share one idea: something leaves and can no longer be seen. 蒸 (steam) plus 発 (send out) gives steamed away, like water vanishing into air or a person vanishing without a trace.
蒸 — grass 艹 + 丞 (phonetic) + fire 灬
Originally depicted plant stalks (艹) being heated over fire (灬), with 丞 providing the sound. The character first meant rising steam from burning hemp stalks used as torches, then broadened to mean steaming food or vapor rising. Modern uses extend metaphorically to 'flourishing' or 'thriving.'