Tongue and groove, mortise and tenon, rabbet and dado and biscuit are all wood joints. Through dovetail, butt and box are other common types of wood joints.
Tongue and groove is used to join two pieces of wood along a long edge. A tongue cut in one piece is joined with a groove that runs along the edge of the other piece. Mortise and tenon joins two pieces of wood at an angle, where a tenon cut at the end of one piece is joined with a mortise in the other. Rabbet and dado joins the end of two boards at a right angle by eliminating part of the thickness of one piece. Biscuits are disks that work like a floating tenon, where the matching slots cut into each piece of wood accepts half of the biscuit.
The simplest way to join two pieces of wood is the butt joint. It is used to increase the width of a piece or the strength and thickness of a member. Tails and pins are the parts of a dovetail joint. Tails are flared shapes cut through one piece of wood and pins are slender shapes cut through the other piece. Through dovetail joints are used to join chests and small boxes. Box joints join two pieces at a corner by interlocking straight cut fingers.