Particleboard

Particleboard is an engineered panel made from wood chips and particles (coarser and less uniform than the fibers in hardboard or MDF) bonded with resin under heat and pressure. It's the core material behind most flat-pack and budget furniture, almost always faced with a laminate, veneer, or melamine skin rather than left bare, since the particle surface itself doesn't finish or show grain attractively.

Its defining weakness is fastener holding power -- a screw driven directly into particleboard has relatively little to grip, and repeated insertion/removal strips the hole out quickly, which is exactly why particleboard furniture leans so heavily on threaded inserts and cam-lock fittings rather than screws threaded directly into the material. It's also notably heavier than plywood of the same dimensions and far more vulnerable to swelling and crumbling if it gets wet.