critical massn.

Brit.

/ˌkrɪtᵻkl ˈmas/, U.S.

/ˌkrɪdək(ə)l ˈmæs/

Origin: Formed within English, by compounding. Etymons: critical adj., mass n.²

Etymology: < critical adj. + mass n.²

1. Nuclear Physics. The minimum mass or size of fissile material required in a nuclear reactor, bomb, etc., to sustain a steady chain reaction. Cf. critical adj. 4b.

ΘΚΠ

the world > matter > physics > atomic nucleus > nuclear fission > [noun] > minimum of fissile material

critical size1940

critical mass1941

crit1957

1941 in M. Gowing Brit. & Atomic Energy 1939–45 (1964) App. ii. 402 For a low critical mass, the material must be as dense as possible.

1946 E. S. C. Smith et al. Appl. Atomic Power 202 No explosion occurs at all unless the mass of the fissionable material exceeds the critical mass.

1995 Gazette (Montreal) (Nexis) 15 Feb. b7 A metal sphere the size of a tennis ball, 11-13 kg in weight, would form a critical mass sufficient for a bomb.

2002 N.Y. Rev. Bks. 7 Nov. 70/2 The critical mass..is determined by a competition between escape of neutrons from the surface of the fissionable material and the creation of neutrons in the interior during the fission process.

2. The minimum size, level, or quantity that something needs to reach in order to achieve an effect or outcome.Originally figurative as part of an extended metaphor; cf. sense 1.

ΘΚΠ

the world > relative properties > quantity > sufficient quantity, amount, or degree > [noun]

fillc893

enoughOE

no lack (of)c1305

sufficiencec1380

suffisancec1381

suffisance1390

sufficienta1450

sufficienty1450

sufficient1470

store1471

sufficientlyc1485

sufficiency1531

satiety1569

strength1593

competence1600

sufficiency1608

competency1616

quantum sufficit1693

quantum suff.1763

adequacy1790

quant. suff.1799

critical mass1947

1947 Kenosha (Wisconsin) Evening News 13 Jan. (Home ed.) 6/3 Time probably was when all these elements were at rest within that great atomic pile of liberalism known as the New Deal. But somewhere in the proceedings..the darn thing must have reached a critical mass and exploded.

1986 Dædalus Spring 117 Modern scientific investigation requires a critical mass of researchers who are in a position to help one another.

2007 Wired Apr. 126/1 During the Internet boom, companies..simply bought their way into new markets when promising technologies reached critical mass.

This entry has been updated (OED Third Edition, March 2022).

单词	critical mass
释义	critical massn. Brit. /ˌkrɪtᵻkl ˈmas/, U.S. /ˌkrɪdək(ə)l ˈmæs/ Origin: Formed within English, by compounding. Etymons: critical adj., mass n.² Etymology: < critical adj. + mass n.² 1. Nuclear Physics. The minimum mass or size of fissile material required in a nuclear reactor, bomb, etc., to sustain a steady chain reaction. Cf. critical adj. 4b. ΘΚΠ the world > matter > physics > atomic nucleus > nuclear fission > [noun] > minimum of fissile material critical size1940 critical mass1941 crit1957 1941 in M. Gowing Brit. & Atomic Energy 1939–45 (1964) App. ii. 402 For a low critical mass, the material must be as dense as possible. 1946 E. S. C. Smith et al. Appl. Atomic Power 202 No explosion occurs at all unless the mass of the fissionable material exceeds the critical mass. 1995 Gazette (Montreal) (Nexis) 15 Feb. b7 A metal sphere the size of a tennis ball, 11-13 kg in weight, would form a critical mass sufficient for a bomb. 2002 N.Y. Rev. Bks. 7 Nov. 70/2 The critical mass..is determined by a competition between escape of neutrons from the surface of the fissionable material and the creation of neutrons in the interior during the fission process. 2. The minimum size, level, or quantity that something needs to reach in order to achieve an effect or outcome.Originally figurative as part of an extended metaphor; cf. sense 1. ΘΚΠ the world > relative properties > quantity > sufficient quantity, amount, or degree > [noun] fillc893 enoughOE no lack (of)c1305 sufficiencec1380 suffisancec1381 suffisance1390 sufficienta1450 sufficienty1450 sufficient1470 store1471 sufficientlyc1485 sufficiency1531 satiety1569 strength1593 competence1600 sufficiency1608 competency1616 quantum sufficit1693 quantum suff.1763 adequacy1790 quant. suff.1799 critical mass1947 1947 Kenosha (Wisconsin) Evening News 13 Jan. (Home ed.) 6/3 Time probably was when all these elements were at rest within that great atomic pile of liberalism known as the New Deal. But somewhere in the proceedings..the darn thing must have reached a critical mass and exploded. 1986 Dædalus Spring 117 Modern scientific investigation requires a critical mass of researchers who are in a position to help one another. 2007 Wired Apr. 126/1 During the Internet boom, companies..simply bought their way into new markets when promising technologies reached critical mass. This entry has been updated (OED Third Edition, March 2022). < n.1941
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