Beadboard wainscoting is either installed as tongue and groove boards or as tongue and groove sheets, the latter being the more cost-effective option. Consisting of a baseboard, the beadboard and a cap (whether it be a chair rail, a plate rail or a picture rail), beadboard wainscoting is really a quite simple system. In fact, it's self-explanatory name comes from the round bead along its edge that disguises the joint between strips.
Hundreds of years since its conception, wainscoting is still used to dress up areas that get a lot of wear and tear. I'm especially fond of beadboard wainscoting in bathrooms!