A biscuit jointer is a woodworking tool designed to create precise slots in wood panels for the insertion of biscuits, small oval-shaped pieces of wood. These slots, when aligned and glued, form strong and stable joints between two pieces of wood.

A biscuit jointer consists of a cutting blade mounted on a base with a fence. The fence guides the tool along the edge of the wood, while the blade cuts a slot to the desired depth. The size of the slot corresponds to the size of the biscuit you'll be using.

Benefits of Using a Biscuit Jointer:
Strong joints: Biscuit joints provide excellent strength and stability
Alignment: The biscuits help align the pieces of wood accurately
Versatility: Suitable for various woodworking projects, including cabinets, shelves, and tabletops
Time-saving: Faster and more efficient than traditional joinery methods

source: https://www.toolstop.co.uk/blog/knowledge-base/what-is-a-biscuit-jointer