R.U.R. (Rossum's Universal Robots) is the title of the play, and also of the factory that makes robots in the play. Interestingly, the bit in parenthesis ("Rossum's Universal Robots") was actually in English in the original, even though the play itself was in Czech. Perhaps this was because factories and industrial production was associated with the U.S. and-or England.
Obviously, the title emphasizes the importance of the factory and of mass production. Čapek could have titled the play Robots, but he felt it was important to get the industrial process in there. The title also makes a parallel between the creative process of the play and the creative process of the factory. Both the play and the factory have the same name, and both are in the business of creating robots. So the title creates a parallel between building people with your brain, and building people in a factory. The play is filled with fake people pretending to be… fake people. Industrialization will make a world full of fakes miming fakes—but with snappy brand names.