In general, "drop off" means to arrive, give someone something, and then leave. So "I will drop off the key" = "I will go to your house, give you the key, and then leave." "I will stop by the school to drop off my son's lunch" = "I will go to the school, give my son his lunch, and then leave."

You can drop off just about anything. drop off = go somewhere and leave something there, then move on Examples: Can you come round about 8 and drop off the keys to the car? It can be used in the situation where people break up. However, it is used in many situations.

Yes, it references two people who were living together. They break-up, and the one who is moving out has to drop-off their copy of the house key after they move out because the one staying in the house does not want them having the key anymore.

Try to remember the phrasal verb with this pattern: "drop off (something/someone) at (location)". It usually means to deliver something, and if you have some longer text, you'll probably see the location is already mentioned. Can you drop off the key at my work? Drop me off at the corner, please. I've just dropped her off at the station and am on my way home. You'll notice "drop off" is separable. If you don't use an object or location, it means to go to sleep (in a place where you usually don't sleep). eg. While watching the movie, I began to drop off. She divorced him because he would always drop off while she was talking to him.

Thank you very much.