REMINDER

[noun] [C]A reminder is a letter, note or message which tells someone to do something.When he forgot to pay his rent, his landlady sent him a reminder (= a note asking for payment).She gave her secretary a gentle reminder that she needed the documents by 5 o'clock. [+ that clause]She let me go, with a final reminder to be back before 11pm. [+ to infinitive]A reminder is also a person or thing which makes you think of a particular person or event.He described the monument as a chilling reminder of a tragedy that must never be repeated.