Sign, saying or image that anticipates, sometimes only for the one who rereads, something that will happen later in the work.
In The Death of Ivan Ilyich
Once he climbed a little stepladder to show the upholsterer, who did not understand, how he wanted the drapery; he missed his footing and fell, but, as a strong and agile man, he caught himself, and only struck his side on the window-frame handle.
The fall from the stepladder seems an unimportant episode: he catches himself and only "struck his side." Later Ivan Ilyich will attribute the illness to this tumble, and the scene reveals itself to be the beginning of the end.