Flooring Terminolgy

Tongue & Groove - The matching milling profiles on opposite long edges of the floor that allow it to be installed. Flooring is nailed through the tongue.
End-match - End-matching refers to the tongue and groove profile in the ends (narrow edges) of the flooring. End-matching in non-structural and serves primarily to ensure that the ends are square to the edges.
Back Relief - Grooves or fluting in the bottom of the boards that ensure the flooring sits flat on the underlayment and has air circulation around it.
Micro-bevel - Small angled reliefs of the long edges of the floor, found on prefinished floors this eliminates the danger of a sharp square edge in overwood situations. With site finished flooring, microbevels are not needed becuase the floor is sanded smooth as a whole after installation and prior to finishing.