reminder
//rɪˈmaɪndər//
Noun
reminderSingular
remindersPlural
1
Something that causes you to remember or think about something; a thing that helps you not to forget something you need to do or know.
I set a reminder on my phone so I don't forget the meeting.
2
A message, note, or notification designed to prompt someone to remember to do something or to recall information.
I set a reminder on my phone to call the doctor tomorrow.
3
Something that serves as evidence or a sign of a past event or situation.
The old photograph was a reminder of happier times.