Tongue & Groove Paneling Profiles
T&G paneling has the greatest variation in profile - the outline or shape of the board. How distinct or shadowed the line between the boards appears after installation depends on the shape of the edge. Most TNG patterns are "beveled" on the edges - called a V Edge (as in diagram below). The depth and angle of the beveling determines how distinct the edges appear.
Paneling Patterns without any V Edge are referred to as Flush-Joint (cedar, pine) or Butt-Joint (redwood). Flush-Joint Tongue and Groove has a similar appearance to classic SHIP LAP Siding.
There is also a T&G pattern profile call "carsiding" that has a V-Groove in the center of the board. This gives the illusion of a narrower board (1x4") when installed but with the time savings of a wider board (1x8").
1x6" Tongue and Groove is the most popular paneling size but a wider 1x8" pattern can be selected to have a more rustic appearance. If you are looking for the classic SHIPLAP paneling look you but you want to hide the nail, you can choose 1x8" T&G and nail through the tongue which is hidden when installed.