1. To alter or moderate something as needed; control: Jane wanted to regulate the amount of heat by turning down the radiator in her room.
2. To change or adjust a device so that it functions properly: The temperature in the fridge needs to be regulated in order to avoid the food freezing if it is turned up too high!
3. To establish conformity or congruity with a principle or rule: Many things in Germany are regulated by the governement as to when something may or can be done or not.