WordNet (r) 3.0 (2006):

Defense Information Systems Agency
    n 1: a combat support agency in the Department of Defense
         responsible for developing and operating and supporting
         information systems to serve the needs of the President and
         the Secretary of Defense and the Joint Chiefs of Staff
         [syn: Defense Information Systems Agency, DISA]

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

Defense Information Systems Agency

   (DISA) Formerly called the Defense Communications Agency
   (DCA), this is the government agency responsible for managing
   the Defense Data Network (DDN) portion of the Internet,
   including the MILNET.  Currently, DISA administers the
   DDN, and supports the user assistance services of the DDN
   NIC.

   (http://disa.mil/).

   (1994-12-01)