1. to add water back to something that has been dehydrated
2. to restore water or fluid to the body after losing it

Examples

• You need to rehydrate the dried mushrooms before cooking them.
• The astronauts rehydrate their freeze-dried meals with hot water.
• After the marathon, she drank sports drinks to rehydrate quickly.
• The doctor advised him to rehydrate slowly after his illness.
• Add warm water to rehydrate the instant soup mix.
• Athletes must rehydrate during long training sessions.
• The camping meal will rehydrate in just five minutes.