nounC1Very rare — outside the 30,000 commonest English words, so you will meet it in writing rather than in speechToo rare in one of the two pools to compare — fewer than 20 uses in speech or in writing
Chipboard is a cheap board pressed from wood chips and glue. A sheet of chipboard.
It is strong flat and useless on edge, and a screw into the edge will pull straight out. Chipboard swells and never recovers once it gets wet, which is why it fails under sinks.