c.1300, "store, treasure," from Old French garison "defense" (Modern French guérison "cure, recovery, healing") from garir "defend" (see garret). Meaning "fortified stronghold" is from early 15c.; that of "body of troops in a fortress" is from mid-15c., a sense taken over from Middle English garnison "body of armed men" (late 14c.), from Old French garnison "provision, munitions," from garnir "to furnish, provide."