Also an acronym for
Network-Attached Storage, a term used for "smart" devices that provide high-level data storage services through a network. Different from
SAN in that a NAS device usually provides at least a filesystem-like interface while SAN devices are accessed at block level, and that NAS usually uses the normal communication network while SAN uses a separate, dedicated storage network.
Basically, any NFS or SMB file-sharing server provides an NAS service, but the term is more often used for plug and play - like devices than for general-purpose workstations that just happen to be dedicated to file sharing.