balayage
noun [ U ] uk/ˈbæl.eɪ.ɑːʒ/ us/ˈbæl.eɪ.ɑːʒ/
（根部颜色较深，沿发梢方向逐渐变浅而看起来很自然的）渐层染发
a method of hair colouring in which colour is painted onto someone's hair thickly at the ends and less and less thickly towards the head, creating a natural look
Balayage is the easiest hair highlighting system ever. 渐层染发绝对是最容易的挑染头发的方法。