Någon, något, and några?
These words have a few meanings depending on the context. Most commonly, they will mean some, a few or any when describing something else. They have to agree in gender or number with what they describe, thus it's någon bok (any/some book), något hus (any/some house) and några stenar (some/any/a few stones).
Furthermore, when used on their own as pronouns,
någon means someone or anyone.
något means something or anything.
några means some (plural of someone/something) or any (plural of anyone/anything).
It might seem strange that both some and any can translate here, but context will tell.
You might come across the word någonting in Swedish. It means just the same as något, but is a little more formal.