brassiere
Synonym discussion
Sense: noun/1
Brassiere is a formal or somewhat old-fashioned word for the garment that supports the breasts. In ordinary conversation, most speakers simply say bra, which is shorter and much more natural in everyday speech. Underwear is a broader word for clothes worn under outer clothes, so it is less exact when you mean this single item. Lingerie also reaches wider: it often refers to women's underclothes as stylish or attractive fashion items, not just one breast-supporting garment. Because of that, an old catalog or receipt may say brassiere, while a modern shopper is more likely to ask for a bra size.
Common collocations
Etymology
Borrowed into English from French brassière. In French the word first referred to a close-fitting upper garment, and in English it later narrowed to the meaning of a breast-supporting undergarment.