The word robot apparently dates back to 1920, from a play by Czech author Karel Capek called R.U.R., or "Rossum's Universal Robots."

Capek is the founder of the Czech school of science fiction writers and an annual award given in the field of science fiction writing in Prague bears his name. This play introduced the word 'robot' first into Czech in its present meaning and then on to the world's languages.

Mr. DOMAIN: ...a working machine must not want to play the fiddle, must not feel happy, must not do a whole lot of other things. A petrol motor must not have tassels or ornaments, Miss Glory. And to manufacture artificial workers is the same thing as to manufacture motors. The process must be the simplest, and the product must be the best from a practical point of view. What sort of worker do you think is the best from a practical point of view?

Miss GLORY: The best? Perhaps the one who is most honest and hard-working.

Mr. DOMAIN: No, the cheapest. The one whose needs are the smallest. Young Rossum invented a worker with the minimum amount of requirements. He had to simplify him. He rejected everything that did not contribute directly to the progress of work. He rejected everything that makes man more expensive. In fact, he rejected man and made the Robot. My dear Miss Glory, the Robots are not people. Mechanically they are more perfect than we are, they have an enormously developed intelligence, but they have no soul.

More etymological trivia:

Some references state that term 'robot' was derived from the Czech word robota, meaning 'work', while others propose that robota actually means 'forced workers' or 'slaves.' This latter view would certainly fit the point that Capek was trying to make, because his robots eventually rebelled against their creators, ran amok, and tried to wipe out the human race.

Back to the etymology:

However, as is usually the case with words, the truth of the matter is a little more convoluted. In the days when Czechoslovakia was a feudal society, 'robota' referred to the two or three days of the week that peasants were obliged to leave their own fields to work without remuneration on the lands of noblemen. For a long time after the feudal system had passed away, robota continued to be used to describe work that one wasn't exactly doing voluntarily or for fun, while today's younger Czechs and Slovaks tend to use robota to refer to work that's boring or uninteresting.