Word, sentence or image that returns several times throughout the work, tied to a character or an idea, and gains meaning with each return.
In Madame Bovary
Fate is to blame!
"Fatalidade" (fate) appears as a word for effect in Rodolphe's letter and returns in the last chapter, in Charles's mouth. The repetition links the seducer who uses it to escape and the husband who uses it to forgive, and each return changes its meaning.
It was fate's fault!
Subscription
The explanation of each passage, in every device and in every work, comes with a subscription.