In Star Wars, the robot name C-3PO doesn't stand for anything, though there are unsubstantiated reports that the name was inspired by a landmark in George Lucas' or Steven Spielberg's hometown. C-3PO is a protocol droid specifically designed to interact with organics.
The acronym R2D2 stands for "Reel 2 Dialogue 2". It was an editor's code for cans of film on the film American Graffitti, from which George Lucas got the name for the Star Wars robot.
C-3PO was inducted into the Robot Hall of Fame in 2004, joining R2-D2, which had been inducted the previous year.
In the news, an actor who played Star Wars robot C-3PO is appealing for information after his life sized model of R2-D2 was stolen from his home. The model, complete with working lights and noises, was nabbed in a break-in just days before Christmas. Catch more here.