R.U.R.

Rico says that stands for Rossum's Universal Robots, a 1920 science fiction play in the Czech language by Karel Čapek. Rossum's Universal Robots was an English phrase used as the subtitle in the Czech original. It premiered in 1921, and introduced the word "robot" to the English language and to science fiction as a whole. (Not to be confused with Rodents of Unusual Size, from The Princess Bride):

This all came up because Rico saw a large truck with Rossum on the side whilst on his recent trip down the Rhine, and one thing (in Rico's head, anyway) led to another...