WordNet (r) 3.0 (2006):

file server
    n 1: (computer science) a digital computer that provides
         workstations on a network with controlled access to shared
         resources

The Free On-line Dictionary of Computing (30 December 2018):

file server

   Hardware and software that together provide file-handling and
   storage functions for multiple users on a local area
   network.  The most common choices for file server software
   are Sun Microsystems' Network File System for Unix and
   Novell Netware for IBM PC compatibles.  There is also a
   version of NFS for PCs called PC-NFS.  Storing files on a
   file server saves having multiple copies stored on individual
   computers, thus economising on disk space and also makes
   administrating and updating the files easier.