To restock means to fill something back up with supplies after they've been used or sold. When a grocery store restocks its shelves, workers bring out new boxes of cereal, cans of soup, and cartons of milk to replace what customers have bought. When you restock your pencil case for school, you add new pencils, erasers, and pens to replace the ones you've used up or lost.

A store's stock is all the items it has available to sell. When that stock runs low, someone needs to restock it. Libraries restock their shelves with returned books. Cafeterias restock their lunch trays. Your family might restock the pantry after a big shopping trip.

Restocking happens everywhere: restaurants restock their kitchens before dinner service, teachers restock classroom supplies before the school year starts, and vending machines get restocked when they run out of snacks. The key idea is replenishment: bringing supplies back up to where they should be so everything can keep running smoothly.