Plywood

Plywood is an engineered sheet good made from thin layers of wood veneer glued together, with each layer's grain direction rotated 90 degrees from the one below it. That alternating structure is deliberate: it makes plywood dramatically more dimensionally stable than solid wood of the same thickness, resistant to splitting, and strong in both directions rather than only along the grain. Like MDF, plywood's edges expose its structure (visible alternating layers, in this case) and typically need edge banding or trim to look finished.