Some means an unspecified amount or number of something: not all, not none, but a portion that isn't precisely counted. When your teacher says “some students finished early,” she means a few kids, but she's not saying exactly how many. When you eat some of your sandwich, you're eating part of it, not the whole thing.

The word works differently depending on what you're talking about. With things you can count, like cookies, some usually means a small number: “Can I have some cookies?” probably means two or three, not twenty. With things you can't count individually, like water or sand, some just means a quantity: “I need some water” or “There's some sand in my shoe.”

You use some when the exact amount doesn't matter or when you don't know it. “Some people love mushrooms” acknowledges that plenty of people do, without claiming it's everyone or specifying a percentage. The opposite of some could be all, none, or no, depending on context: “Some kids went home” vs. “All the kids went home” or “No kids went home.”

In questions, some often suggests you're expecting a yes: “Would you like some juice?” sounds more welcoming than “Would you like any juice?” That small difference in word choice changes how the question feels.