The term “cliffhanger” began with a moment that was not a metaphor at all. In 1873, Thomas Hardy published his novel A Pair of Blue Eyes in weekly installments. In one chapter, the hero slips while climbing a cliff and ends up dangling from the edge, staring at the sea far below. The installment ends right there, and readers had to wait a full week to learn whether he survived.

The scene became so famous that people began using “cliffhanger” to describe any story that ends with a moment of unresolved tension. Earlier authors such as Charles Dickens often used suspenseful endings in serialized fiction, but Hardy’s literal cliff scene is the one that gave the device its name.