spareroles
nounUK /ˌspeə ˈrəʊlz/
US /ˌsper ˈroʊlz/
Extra wheels or parts you keep in case something breaks.
Dad keeps spareroles in the garage for the old cart.
OTHER MEANINGS
2. Extra jobs or parts in a play that someone can take over.
The understudy learned the spareroles just in case.
3. Additional turns or duties kept in reserve.
The team listed spareroles for the busy weekend.
4. Unused positions on a list that can be filled later.
There were two spareroles left on the sign-up sheet.