柯林斯詞典allergen /??l??d??n/ (allergens) 1. N-COUNT An allergen is a substance that causes an allergic reaction in someone. 過敏源[技術] 返回 allergen劍橋詞典a substance that can cause an allergy (= condition of the body reacting badly to something) but is not harmful to most people （引起過敏反應的）變應原；過敏原 返回 allergen