Pretty straightforward. Prometheus is... bound. The play takes place after Prometheus has been tied to a rock as punishment for stealing fire from the gods and giving it to humans, so the title basically summarizes the play's initial situation—sort of like, say, Mothra Versus Godzilla. And just like modern monster movies, Aeschylus's play had a sequel. Can you guess its title? You got it: Prometheus Unbound.