Karel Čapek needed a name for the manufactured workers in his 1920 play R.U.R. He thought of labori, and by his own account his brother Josef, busy painting, said through the brush in his mouth to call them roboti, from robota, the Czech for the unpaid labour a serf owed his lord. Čapek’s robots weren’t metal. They were made of a kind of artificial flesh, mixed in vats, close enough to people that the whole play turns on whether they are. The clanking came later, from everyone else. The word began as the name of a debt, a duty owed, and only afterwards learned to move like a machine.