As used in this chapter:
(1) “National Defense Act” means an act of Congress, entitled, “An Act for making further and more effectual provisions for the national defense, and for other purposes” approved by the President, June 3, 1916, and any and all acts amendatory and supplementary thereto.
(2) “Unit” shall mean any part of the Delaware National Guard designated a “unit” by order of the Adjutant General.