moldboard: wedge formed by the curved part of a steel plow blade that turns the furrow
wedge: something solid that is usable as an inclined plane (shaped like a V) that can be pushed between two things to separate them
tee hinge: a hinge that looks like the letter T when it is opened; similar to a strap hinge except that one strap has been replaced by half of a butt hinge that can be mortised flush into the stationary frame