▪ I. bra1
(brɑː)
Formerly also (as sing.) bras.
Colloq. abbrev. of brassière. Also attrib.
| 1936 W. B. M. Ferguson Somewhere off Borneo i. 26 She wore nothing but a ‘bras’, the briefest of French knickers, and the sheerest of white silk hose. 1936 New Yorker 28 Mar. 7 (Advt.), Bras..50 c. 1937 Night & Day 30 Sept. 27 (Advt.), The Bra is one of the famous ‘Alphabet’ Bra's. 1948 Punch 2 June iii/1 (Advt.), The two-piece is Rayon-Lastex with a bra adjustable in three..ways. 1959 Manch. Guardian 3 July 5/6 Elasticated sides and reinforced bra top. 1968 J. Ironside Fashion Alphabet 66 Bra-slip, petticoat or slip with top part shaped like a brassière and giving the support of a brassière. |
▸ orig. U.S. Freq. more fully auto bra, car bra, nose bra. A protective cover fitted over the front of a vehicle to guard against wear and tear; (often) spec. one also containing materials intended to absorb the microwaves used in police radar equipment and thus reduce the risk of detection when speeding (also more fully stealth bra).
| 1971 Sheboygan (Wisconsin) Press 16 June 4/4 A Los Angeles auto accessories salesman is featuring a padded ‘car bra’ as an ideal gift for Father's Day. 1980 Car & Driver Dec. 142/1 All of them are similar in construction, consisting of a vinyl stone-shield, or ‘bra’, lined with microwave absorber. 1987 Los Angeles Times (Nexis) 8 Jan. v. 18/1 Should you wish to save the grill of your car from rocks, birds and debris, there is an expanded line of ‘auto bras’ that are custom tailored to fit your car. 1989 Car & Driver Sept. 140/2 The Stealth Bra incorporates microwave elements that minimize the return signal from police radar. 1998 Edmonton (Alberta) Sun (Nexis) 10 July ‘Nose-Bras’ are becoming more and more popular as a means of reducing rock chips, bug damage, etc. to the paint on the front of cars. |
▪ II. bra2 Quantum Mech.
(brɑː)
[f. bracket: cf. ket.]
A vector in Hilbert space that is the complex conjugate of a ket and is symbolized by bra vector.
| 1947 P. A. M. Dirac Princ. Quantum Mech. (ed. 3) i. 19 We shall call the new vectors bra vectors, or simply bras, and denote a general one of them by the symbol {bra}, the mirror image of the symbol for a ket vector. 1957 F. Mandl Quantum Mech. (ed. 2) v. 102 The ket and bra vectors correspond to the column and row vectors of matrix algebra. 1972 J. M. Jauch in Salam & Wigner Aspects Quantum Theory ix. 164 These examples..show how Dirac's bra and ket notation, so effective as an operational device, may be based on a mathematically rigorous foundation. 1973 S. Wieder Foundations Quantum Theory iii. 47 The inner product b. a is a complex scalar obtained by multiplying the bra form of b by the ket form of a. 1974 [see ket]. |
▪ III. bra
obs. form of brae.