Azure Data Lake Storage is optimized performance for parallel analytics workloads A key mechanism that allows Azure Data Lake Storage Gen2 to provide file system performance at object storage scale and prices is the addition of a hierarchical namespace. This allows the collection of objects/files within an account to be organized into a hierarchy of directories and nested subdirectories in the same way that the file system on your computer is organized.
References:
https://docs.microsoft.com/en-us/azure/storage/blobs/data-lake-storage-namespace