Is it trim or moulding?

The terms trim and moulding are frequently used interchangeably in construction and interior design, but there is a subtle distinction between the two concepts. Moulding is a specific type of millwork characterized by its distinct, ornamental profile—such as the curved contours of crown molding, chair rails, or decorative casing—designed specifically to add architectural detail and smooth transitions to a room. Trim, on the other hand, is a broader, overarching umbrella term that encompasses all the wood, MDF, or PVC materials used to finish and cap off raw edges in a building, which includes functional boards like plain baseboards, window sills, and door jambs alongside decorative mouldings. Therefore, while all moulding is technically a form of trim, not all trim possesses the decorative, profiled characteristics that define traditional moulding.