Here's why:
* Concrete nouns refer to things you can physically touch and experience with your senses, like a book, a tree, or a dog.
* Abstract nouns refer to ideas, concepts, qualities, or feelings that you can't touch or physically see, like love, happiness, justice, or freedom.
While the world is a physical place, "world" as a noun represents a broader concept encompassing everything that exists, including all living things, planets, stars, and the universe itself. This concept is intangible and abstract.