[This is a fast-access FAQ excerpt.]
"Brassiere" is first recorded in a Canadian advertisement of
1911, and in the U.S. Index of Patents for the year 1910 (published
in 1911). Dictionaries derive it from obsolete (17th century)
French brassiere = "bodice", from Old French braciere = "arm
protector", from bras = "arm". (The French word for bra is
soutien-gorge, literally "support-throat".)
In the southern U.S., a bra is sometimes called a "tit-sling".
This has an obvious derivation.
Wallace Reyburn, to whom Thomas Crapper owes his current fame,
wrote a later book describing a lawsuit over rights to the bra,
fought from 1934 to 1938 in New York, between a German-born
designer, Otto Titzling (1884-1942), and a French-born designer,
Philippe de Brassiere. Martin Gardner, in Time Travel and Other
Mathematical Bewilderments (Freeman, 1988, ISBN 0-7107-1925-8),
p. 137, says: "The book by Wallace Reyburn Flushed with Pride: The
Story of Thomas Crapper does exist. For many years I assumed that
Reyburn's book was the funniest plumbing hoax since H. L. Mencken
wrote his fake history of the bathtub. [...] Reyburn wrote a later
book titled Bust-up: The Uplifting Tale of Otto Titzling and the
Development of the Bra. It turns out, though, that both Thomas
Crapper and Otto Titzling were real people, and neither of
Reyburn's books is entirely a hoax."
On its AOL message board, Merriam-Webster Editorial Department
writes: "dull though it may be, all the available etymological
evidence indicates that the word derives from the French 'brassiere'
[...]; there are many examples of the use of 'brassiere' in the
women's apparel sense throughout the 19th century -- in French.
[...] Given the word's history and that country's language
heritage, it is not surprising that the first occurrence of the
"brassiere" in English comes from Canada. [...] We can find no
verifiable evidence that anyone named either 'Titzling' or
'Brassiere' had anything to do with the origin of the term."