Amazon S3 stores data as objects within resources called "buckets". Object storage, also called object-based storage, is an approach to addressing and manipulating data storage as discrete units, called objects. Objects are kept inside a single repository, and are not nested as files inside a folder inside other folders.
Object storage keeps the blocks of data that make up a file together and adds all of its associated metadata to that file. But object storage also adds extended metadata to the file and eliminates the hierarchical structure used in file storage, placing everything into a flat address space, called a storage pool In AWS it is called S3 bucket.
Coming to the second part of your question:-
Object storage is a perfect solution for huge amounts of data
object storage overcomes many of the limitations that file storage faces. Think of file storage as a warehouse. When you first put a box of files in there, it seems like you have plenty of space. But as your data needs grow, you’ll fill up the warehouse to capacity before you know it. Object storage, on the other hand, is like the warehouse, except with no roof.