Jointer is a tool used to join two pieces of wood together. It is used to create a smooth, flat surface on the wood and to create a strong, seamless joint. The tool consists of a base with a motor, a blade, and a
From Wikipedia
A jointer or in some configurations, a jointer-planer is a woodworking machine used to produce a flat surface along a board's length. As a jointer, the machine operates on the narrow edge of boards, preparing them for use in a butt joint often used to glue boards into panels. A planer-jointer setup has the width that enables smoothing ('surface planing') and leveling the faces (widths) of boards small enough to fit the width of the tables and blades.