corrugated cardboard; cardboard box
Refers to the material itself or, by extension, a box made of it. Often written in katakana.
引っ越しの荷物を段ボールに詰める。
I pack moving items into cardboard boxes.
この段ボールはリサイクルに出してください。
Please put this cardboard out for recycling.
I put the books in a cardboard box and shipped them.
I folded up the used cardboard boxes and stacked them together.
I made a rocket out of cardboard with my kid.
On garbage day I crushed the cardboard boxes and put them out.