When you only let your dog have a cup of food a day, this is an example of a situation where you ration your dog's food.
Food provided to soldiers is an example of a ration.
The amount of food you are allowed during a war or other time of scarcity is an example of a ration.
Our present health care system is rationed only to those who can afford it because of unnecessary high cost, lack of insurance coverage by 47 million people, and exorbitant prescription prices.
We rationed ourselves to three sips of water a day until we were rescued.