[verb] To injure a joint by temporarily forcing the bone out of its normal socket.
[noun] In men's gymnastics, a rotating of the shoulders when performing a backwards turn on the still rings. Many skills in acrobatics appear to involve dislocating a joint, when they actually do not.
Dislocation generally is taken to mean a joint is beyond the control of the muscles and tendons surrounding it.
A Controlled Dislocation is controlled that it was intentional - the adjacent muscles and tendons might not be in control, but the movement can be at least partially controlled, and reset to a normal range.
Compate with Overextension
Definition based on the Contortion Glossary by Greg Ullman and Tige Young