/ˈmek.ə.nɪ.zəm/
a set of moving parts in a machine that performs a task 机械装置；机件
a delicate watch mechanism
精致的手表机件
a system of parts in a living thing that together perform a particular function （生物体内的）机制，构造
the balance mechanism in the ears
耳内的平衡机制
Pain acts as a natural defence mechanism.
疼痛起着自然防护机制的作用。