The term applique is also used in the context of military systems. An applique system is one which can be 'retrofitted' or 'added on' to an existing system without being part of the original design specification. As an example, when reactive armor was first invented, there were applique kits available to retrofit then-current armored vehicles with the new armor.

Ap`pli`qué" [F., fr. appliquer to put on.]

Ornamented with a pattern (which has been cut out of another color or stuff) applied or transferred to a foundation; as, appliqué lace; appliqué work.

© Webster 1913.