The definition of a reminder is a person or thing that helps one remember something.
(noun)
- An example of a reminder is a to ask your husband to remind you of an impending business trip at least a week before he has to leave.
- An example of a reminder is to write a note so you won't forget your lunch in the morning.
- An example of a reminder is to tell your child to go to the bathroom before you get in the car.