What is the gapcrackflaw in the top of a cardboard box called?

Designer Multi-Product Cardboard Packaging Box with Message cardboard box with slot Raffle Ticket Box Donation Collection Ballot Box Reusable Sturdy thick Cardboard Box with Slot comment Suggestion Box With Removable Header 6H x 6W x 6D, cardboard slot sculpture You can even use the box to urge attendees to drop their name badges inside for recycling after the event Made of corrugated cardboard and is 100% recyclable

cardboard slot machine CARDBOARD BOX WITH A CARRYING HANDLE George E Thibault , Somerset , Mass slot at its free edge into which slot the adjacent portions of the