Introducing an object/dialogue/activity and then bringing it back in a different context, infusing it with new a meaning.
Example for an object plant/pay-off: In Sideways, a wine bottle dated back to 1961 is introduced as one of Miles’ most prized possessions. He looks forward to drinking this wine at a special occasion. Later in the movie, after he has been to his ex-wife’s wedding and realized she will not get back with him; Miles ends up drinking this prized wine in a McDonalds by himself, from a cheap plastic cup.
Example of a dialogue plant/pay-off: In 300, before raping Queen Gorgo, Theron says: “This will not be over quickly. You will not enjoy this. I am not your King.” Near the end of the movie, Gorgo speaks the same words back to him as she thrusts a knife into his chest: “This will not be over quickly. You will not enjoy this. I am not your Queen.”