“止痛”的意思是让疼痛停止或减轻，常常用在吃药或看病的时候。

The meaning of "止痛" is to stop or relieve pain, often used when taking medicine or seeing a doctor.

比如头很疼的时候，你可以吃一片止痛药。

For example, when your head hurts a lot, you can take a painkiller for "止痛".