Trim vs. Molding
Although often used interchangeably, trim is essentially filler where there are gaps, like where drywall meets flooring or cabinetry meets the wall or another cabinet. It may also refer to casing around doors & windows. Molding serves a largely decorative purpose, with the exception of chair rail, which protects the wall from chair dings.
1. Trim is the action taken to cover seams.
2. Molding is the wood or product itself used to cover seams.