brassiere (n.) Look up brassiere at Dictionary.com
18c., "woman's underbodice," from French brassière "child's chemise; shoulder strap" (17c.), from Old French braciere "arm guard" (14c.), from bras "an arm," from Latin bracchium "an arm," from Greek brakhion "an arm" (see brachio-). Modern use is a euphemistic borrowing employed in the garment trade by 1902.