The Free On-line Dictionary of Computing (19 January 2023):

Independent Computing Architecture
ICA

    (ICA) Citrix's proprietary protocol that
   allows client desktop computers to run applications on
   application servers.  Originally used between Windows
   systems, ICA is now also suported on Unix and Macintosh
   desktops and servers as well as some thin client hardware.

   (2012-07-08)