"German POW camp," 1940, from German Stalag, short for stammlager "main camp," from Old High German stam "stem" (from Proto-Germanic *stamniz, from suffixed form of PIE root *sta- "to stand, make or be firm") + Lager "bed, lair, camp, storehouse," from Old High German legar "bed, lair," from Proto-Germanic *legraz, from PIE root *legh- "to lie down, lay."