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

Cardboard Cryogenic Vial Tube Storage box 5x5 place with grid for cardboard box with slot This is a divided box that will fit 12 glasses or 12 jars It comes with an 18 x 12 x 6 outer box Each slot is 3-78 X 4-14 X 5-78 cardboard box with slot This is a second time it is happening, The first time was when I was planning to make DIY Gemstones Picture FrameShadowbox I couldn't find a

cardboard slot sculpture The general term cardboard box includes several types of paper boxes, such as corrugated boxes and chipboard boxes The various shapes of cardboard boxes are