noun
1. : the stub of a ticket (as to a baseball game) retained by the spectator and good for admission to a later performance if the scheduled performance is interrupted during its early part (as, in baseball usually before 4 1/2 innings are over) by rain or bad weather
2. : an extension of the offer of a favor or privilege until a more appropriate or convenient time
decided to pass up the invitation for the moment, but told him we wanted a rain check for transportation across with the last officers who would leave the city — R.A.Gunnison
who smiles, confers a rain check to an untoward hour — Marsden Hartley
— often used with take or give
take a rain check on that dinner