Tolkien called a sudden joyful escape from disaster a eucatastrophe.
Tolkien introduced the term in his 1939 lecture and essay On Fairy-Stories. He formed it from Greek roots meaning “good” and “down-turn,” presenting it as the opposite of catastrophe. In a eucatastrophe, a story’s apparent movement toward ruin is unexpectedly reversed by a saving turn.
For Tolkien, this was not simply a convenient happy ending. He considered it a defining power of fairy stories and connected it with the deepest emotional effect of narrative: the sudden joy of hope restored. He also described the Resurrection as the supreme example of this pattern.
Eucatastrophe is often confused with sub-creation, Tolkien’s term for imaginative world-making. The two ideas are related in his theory of fantasy, but they refer to different things.