Wrestling is a catch-all term for a variety of grappling styles that use take-downs, submission holds and positioning, typically with the goal of pinning your opponent. Most modern wrestling styles (amateur, freestyle) can be traced back to a wrestling style known as "catch wrestling", a British hybrid style founded in the late 1800s.
Mortal Kombat Armageddon is unusual in that the Wrestling style used isn't based on professional wrestling like most other games, but instead is loosely based on freestyle wrestling.
In MKX, while he doesn't use the same style as the old games. One of Jax's Variations is called Wrestler, which gives him access to powerful crushing attacks and grab combos, but also has some parts of his Bionic Arms glow orange.