If you've looked into baseboards or window and door casings, you've probably heard of back band trim However, even if you haven't heard the term.
1x4 with backband on window, 1x6 with backband on entrance
How to Build a Wide, Stacked Crown and Cornice Molding - Do-it
Backband Trim Mouldings One
Wall Moulding Kit for TV Unit , Wainscoting Panelling , Wall
Casing and Backband Baseboard styles, House trim, Architrave
st.hzcdn.com/simgs/e1b121fc0decfc91_4-3549/traditi
The Metro Collection Moulding - Garden State Lumber
Crown Molding Design Ideas and Diagrams
Additional Trim Products - Riverside Millwork Group