1. （通常指用完后）放下， 搁下
If you lay something down, you put it down, usually because you have finished using it.
2. 规定；制定；颁布
If rules or people in authority lay down what people should do or must do, they officially state what they should or must do.
3. 放下（武器）
If someone lays down their weapons, they stop fighting a battle or war and make peace.