Amazon S3 (Simple Storage Service) is a way to store and share files over the internet. Think of it like a big storage closet in the cloud (over the internet).
You can store almost any type of file in S3 like pictures, videos, music, documents and more. Whenever you want to access a file in your S3 closet, you can simply open the door, find the file and open it up. You can also give access to other people so they can find and access the files too. Additionally, you can back up files so you always have a copy saved.