The Enterprise-class was a type of aircraft carrier in use by the United States Navy in the 20th century. The USS George Washington and USS Theodore Roosevelt were Enterprise-class carriers. (TNG novel: Ghost Ship)
In Ghost Ship, the George Washington is described as belonging to the Enterprise-class, despite the fact that the real-life vessel was a ship of the Nimitz-class. The George Washington was not yet in service at the time of the book's writing in 1987. The "Enterprise-class" is an uncertain designation, seeing as the prototype USS Enterprise (CVN-65) led the way for a generation of nuclear powered aircraft carriers, of which the Washington is a part, even though, in the strictest definition, Enterprise is in a class by herself since no other vessels were constructed to her exact specifications.