The Collaborative International Dictionary of English v.0.48:

disa \disa\ n.
   any orchid of the genus Disa, a genus of beautiful orchids
   with dark green leaves and usually hooded flowers; -- they
   are much prized as emblematic flowers in their native
   regions.
   [WordNet 1.5]

WordNet (r) 3.0 (2006):

disa
    n 1: any orchid of the genus Disa; beautiful orchids with dark
         green leaves and usually hooded flowers; much prized as
         emblematic flowers in their native regions
    2: 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]

V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DISA
       Data Interchange Standards Association (org.)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

DISA
       Defense Information Systems Agency (org., mil., USA)


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

DISA

   1.  Defense Information Systems Agency.

   2.  Data Interchange Standards Association.

   (1999-09-18)