What are the differences between the two? I thought that "World" means everything, i.e the same as "Universe". But people seem to think it means the same as "Earth".

What are the differences between the two? I thought that "World" means everything, i.e the same as "Universe" (disclaimer: I'm not making a statement about multiverses here, don't take it as a scientific text). But people seem to think it means the same as "Earth".