the.com/wallboard

means A flat rigid panel, typically of gypsum sandwiched in paper, used to form the interior walls and ceilings of buildings.

from A plain compound of 'wall' and 'board' — board here in its old sense of a flat sheet of processed material, as in 'cardboard' or 'particleboard.' The term emerged in the early 20th century as manufacturers developed factory-made sheet panels to replace wet plaster-and-lath walls, and it's survived since as the trade-catalog name for what most people just call drywall.