洗发水的英文核心词是“shampoo”,源于18世纪印地语“chāmpo”(原指“按摩头皮”),现泛指各类洗发产品,还可作动词表“洗头”,如“I need to buy shampoo”或“My sister shampoos her hair”。细分场景中,干发应急用“dry shampoo”,深层清洁选“clarifying shampoo”(适合去油、去发胶),护色用“color-safe shampoo”。需注意与护发素“conditioner”区分,二者功能不同,正确步骤是“shampoo fi...