re·fresh·er 
/rɪˈfrɛʃɚ/ noun
plural re·fresh·ers /rɪˈfrɛʃɚ/ noun [count] chiefly US : something that helps you to remember something you have forgotten : a reminder about something — usually singular — usually + on ▪ Before we play, I need a refresher on the rules. [=I need someone to remind me about the rules] ▪ Some people need a refresher on how to be polite.
