Trolls are usually named after the first thing they eat, but in some cases, they are named after the sound that the first thing they ate made. In pinball, the tilt sensor is used to prevent the player from cheating by bumping the machine; this may be what Tilt first ate.
In the 2008 Postbag from the Hedge, A message from the wire, it is revealed Tilt got their name from a group of humans playing a pinball machine. One of them said "Tilt!" and the other said "No, Flippa!", with Tilt eating the one that said Tilt and Flippa eating the one that said Flippa.