Meaning

noun an undergarment worn by women to support their breasts

originClipping of brassiere, borrowed from French brassière, from Old French braciere (originally a lining inside armor to protect the arm, but later a garment), from Old French brace (“arm”), from Latin bracchia, plural of Latin bracchium (“forearm”), from Ancient Greek βραχίων (brakhíōn, “forearm”), from Proto-Hellenic *brəkʰús (“short”) (because the forearm is shorter than the upper arm), inherited…

Etymology from Wiktionary, CC BY-SA 3.0