A sign, a saying, or an image that anticipates, sometimes only for the rereader, something that will happen later in the work.
In The Posthumous Memoirs of Brás Cubas
Prudêncio, a houseboy, was my daily horse
The game of riding Prudêncio foreshadows the meeting in chapter LXVIII, in which he, now free, strikes an enslaved man of his with a whip: the violence he received comes back out of him.