NAS means Network attached Storage
A NAS is a small computer with a lot of storage capacity, you can see it as a large hard disk connected to a network. For example, a normal external hard disk is connected to a computer via a USB connection and not to a network. The NAS uses TCP/IP to control the data transfer. The advantage of a NAS is that every computer on the network can join, several operating systems can be there, and so it is a good option for backups or storing large files. Curious about the possibilities, take a look at Nascenter https://www.youtube.com/watch?v=bzAjpS1cFe0