The word drop has several common meanings:

1. To let something fall, either on purpose or by accident. When you drop a glass, it falls to the floor. You might drop your backpack by the door when you get home. Basketball players practice not dropping the ball during a fast break. Sometimes people drop things accidentally because they're distracted or their hands are full.
2. A tiny amount of liquid, shaped like a small bead. A single drop of water hangs from a faucet before falling. Medicine often comes in drops that you squeeze from a small bottle. When someone says “just a drop” of milk in their tea, they mean only a tiny bit. In stories, characters might not have “a drop of water” left.
3. To decrease or fall suddenly. Temperatures drop when a cold front moves through. Your energy level might drop in the afternoon. Test scores can drop if students don't study. The word suggests a quick downward change rather than a slow, gradual one.
4. To stop doing something or end involvement with it. A student might drop a difficult class or drop out of a club that meets too often. When you drop a subject in conversation, you stop talking about it.
5. To take someone or something somewhere and leave them or it there. You can drop a friend off at their house, or drop a package off at the post office.