No, the term "space junk" isn't referring to the movie "Contact" (burn you Jodie Foster for that horrible movie!), it refers to all the debris that humans have dumped, shot or otherwise placed in outer space.
Orbital debris, or “space junk,” is any man-made object in orbit around the Earth that no longer serves a useful purpose. Space junk can be bad news for an orbiting satellite. On February 11, 2009, a U.S. communications satellite owned by a private company called Iridium collided with a non-functioning Russian satellite. The collision destroyed both satellites and created a field of debris that endangers other orbiting satellites.
To minimize the risk of collision between spacecraft and space junk, the U.S. Space Surveillance Network tracks all debris larger than 10 centimeters. These images represent all man-made objects, both functioning and useful objects and debris, currently being tracked. The images were made from models used to track debris in Earth orbit. Of the approximately 19,000 manmade objects larger than 10 centimeters in Earth orbit as of July 2009, most orbit close to the Earth, top image. The lower image shows all items in orbit, both close to and far from the Earth.