: something that calls a memory or thought to the mind
a picture that's a reminder of happier times
There were reminders of him everywhere. Whenever she heard music, or when she played the guitar he had given her, Felicity thought of her grandfather's gravelly voice singing along, happily out of tune. Valerie Tripp
Now a quarter of mortgaged American homes are underwater, and movie montages about cashmere sheets are an irksome reminder of how we can't afford them. Sarah Ball
b
: something (such as a note or notification) designed to prompt or aid the memory
She wrote a reminder about the meeting in her calendar.
I run the risk of missing a reminder because I often silence my phone when I am on the air or recording in the studio. Cat Wilson