Jack Plane
A medium-sized, general purpose plane
Jig
An auxiliary device most often secured to a workpiece to guide it through a tool (or a tool through the workpiece), or to make multiple measurements in a consistent and repeatable fashion
Jigsaw
A power tool using a vertical, reciprocating blade; used for cutting different kinds of materials depending on the type of blade used
Joinery
Connecting pieces of wood together through a variety of means, including using glue and mechanical fasteners, though generally
understood as the use of interlocking or corresponding wooden joints
Jointer
The usually-stationary shop machine that makes a uniform, square surface by removing thin layers of material until the whole board is square
Jointer Plane
A type of plane used to square long edges
Jointer/Planer
A stationary machine that operates as both a jointer and a planer