/ ˈrəʊləʊvə(r); NAmE ˈroʊloʊvər/ noun
1.
[ U ] ( technical ) the act of allowing money that is owed to be paid at a later date
2.
[ U , C ] ( BrE ) a prize of money in a competition or lottery in a particular week, that is added to the prize given in the following week if nobody wins it :
a rollover jackpot
3.
[ U ] ( especially NAmE ) the turning over of a vehicle during an accident