Often used interchangeably, the terms 'baseboard' and 'trim' mean different things.
The Difference Between Baseboard and Trim, for Finish Carpentry:
Baseboard is the wood (or other material) board that runs between the floor and the wall. It usually is between 3’’-8’’ and comes in a variety of materials and profiles.
Trim is a broad term that encompasses baseboard and other trim throughout the home.
Baseboard trim is also referred to as baseboard molding, and molding is another form of trim. Other popular forms of trim include:
Window Casing (Window Trim)
Door Casing (Door Trim)
Panel Molding / Wainscoting
Finally, many pieces are designed for trim can be incorporated in baseboard work. They can include: base caps, stop blocks, plinth blocks, ornamental molding, quarter round (shoe mold), and more.