wattn.

Brit.

/wɒt/, U.S.

/wɑt/

Inflections: Plural watts, unchanged.

Origin: From a proper name. Etymon: proper name James Watt.

Etymology: < the name of James Watt (1736–1819), Scottish engineer and pioneer in the science of energy (best known for developing the condensing steam engine).

1. A unit of electrical power equal to the rate at which work is performed when a current of one ampere flows across a potential difference of one volt. In later use (more generally): a unit of power (as incorporated in the International System of Units), equal to a rate of energy transfer of one joule per second.This unit was proposed by C. W. Siemens in 1882 at the 52nd meeting of the British Association for the Advancement of Science. At the 1948 General Conference on Weights and Measures the watt was redefined in terms of units of energy and time.Often used as a modifier with a preceding numeral to specify the power output of an electrical device, e.g. 40 watt light bulb.Often with combining forms denoting multiples of this unit, as kilowatt, terawatt, etc.

ΘΚΠ

the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > watt

watt1882

1882 C. W. Siemens in Nature 24 Aug. 391/2 The other unit I should suggest adding to the list is that of power. The power conveyed by a current of an Ampère through the difference of potential of a Volt is the unit consistent with the practical system. It might be appropriately called a Watt, in honour of..James Watt... A Watt, then, expresses the rate of an Ampère multiplied by a Volt, whilst a horse-power is 746 Watts, and a Cheval de Vapeur 735.

1886 R. H. Thurston in Jrnl. Franklin Inst. Oct. 265 It was judged that it [sc. a dynamo] might have been driven up to 300,000 watts with safety.

1930 Engineering 21 Mar. 393/1 The panels are illuminated from behind by a standard 40-watt ‘pearl’ lamp.

1967 Canad. Med. Assoc. Jrnl. 7 Oct. 901/2 The patients exercised on a bicycle ergometer in a supine position at an energy level of 25 watts for 10 minutes.

2011 C. D. Ferguson Nucl. Energy: What Everyone needs to Know (e-book ed.) A light bulb powered by 100 watts requires delivery of 100 joules of electrical energy per second in order to light the bulb.

2. As a modifier (with preceding numeral or other adjective), designating something particularly attractive, striking, or powerful; usually esp. designating such a facial expression (typically a smile), as in ——watt grin, ——watt smile, etc.

1913 Electr. Worker Nov. 1137/2 Lovell faced the pitcher with a 30-watt smile.

1985 G. V. Higgins Penance for Jerry Kennedy viii. 67 He gave Dunn a six- or seven-hundred-watt glare.

2000 Edmonton (Alberta) Jrnl. (Nexis) 26 Nov. (Entertainment section) c4 The ex-Beatle has answered a private call to arms by lending his billion-watt celebrity to landmine elimination.

2016 Independent (Nexis) 24 Aug. 9 The nation is no stranger to the ten thousand watt grin of its most accomplished female boxer.

Compounds

watt-hour n. a unit of energy equal to that produced in one hour by a power of one watt (equal to 3600 joules); symbol Wh.Cf. kilowatt-hour n. at kilowatt n. Compounds.

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the world > matter > physics > energy or power of doing work > [noun] > specific quantities or units of energy or work

horsepower1806

foot-pound1847

foot-ton1860

kilogrammetre1866

erg1873

kilerg1873

indicated horsepower1881

metre-ton1881

joule1882

watt-hour1888

manpower1893

horsepower-hour1899

horse1904

1883 Telegr. Jrnl. & Electr. Rev. 24 Feb. 166/1 If you are regarding the measure as 1,000 watt hours, it is not the same as 1,000 watts.

1907 E. Wilson & F. Lydall Electr. Traction I. 379 This can be converted into watt hours per ton mile thus.

2009 Daily Tel. 13 Jan. 13/2 A study has found that on average the wind turbines generate only 214 watt hours a day, less than five per cent of a household's daily electricity needs.

watt-sec n. a unit of energy equal to that produced in one second by a power of one watt (equal to one joule); = watt-second n.

ΘΚΠ

the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > joule

joule1882

coulomb-volt1893

watt-second1893

wattsec1962

1899 Electr. Rev. (U.S.) 7 Apr. 574/1 (table) Joules = watt-secs = 10⁷ ergs.

1962 New Scientist 18 Jan. 157/1 The term ‘wattsec’ is..a common one among radio engineers while ‘joule’ appears to be seldom used in practice.

2013 P. S. Auerbach Field Guide Wilderness Med. (ed. 4) iii. 38 If ventricular fibrillation or asystole is determined, defibrillate one time with 2 watt sec/kg up to 200 watt sec.

watt-second n. a unit of energy equal to that produced in one second by a power of one watt (equal to one joule); symbol Ws.

ΘΚΠ

the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > joule

joule1882

coulomb-volt1893

watt-second1893

wattsec1962

1886 Telegr. Jrnl. & Electr. Rev. 6 Aug. 154/1 I notice in your correspondence columns the expression, ‘number of foot-pounds in a watt’. It should be, ‘in a watt-second or joule’.

1981 Sci. Amer. Dec. 53/1 A photon with a frequency in the visible region of the electromagnetic spectrum has little energy: less than 10⁻¹⁹ joule, or watt-second.

2009 B. Stoppee & J. Stoppee Guide Photogr. & Light xiii. 384/2 Prepare to shell out a few dollars for the big 2,000 watt-second pack.

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

单词	watt
释义	wattn. Brit. /wɒt/, U.S. /wɑt/ Inflections: Plural watts, unchanged. Origin: From a proper name. Etymon: proper name James Watt. Etymology: < the name of James Watt (1736–1819), Scottish engineer and pioneer in the science of energy (best known for developing the condensing steam engine). 1. A unit of electrical power equal to the rate at which work is performed when a current of one ampere flows across a potential difference of one volt. In later use (more generally): a unit of power (as incorporated in the International System of Units), equal to a rate of energy transfer of one joule per second.This unit was proposed by C. W. Siemens in 1882 at the 52nd meeting of the British Association for the Advancement of Science. At the 1948 General Conference on Weights and Measures the watt was redefined in terms of units of energy and time.Often used as a modifier with a preceding numeral to specify the power output of an electrical device, e.g. 40 watt light bulb.Often with combining forms denoting multiples of this unit, as kilowatt, terawatt, etc. ΘΚΠ the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > watt watt1882 1882 C. W. Siemens in Nature 24 Aug. 391/2 The other unit I should suggest adding to the list is that of power. The power conveyed by a current of an Ampère through the difference of potential of a Volt is the unit consistent with the practical system. It might be appropriately called a Watt, in honour of..James Watt... A Watt, then, expresses the rate of an Ampère multiplied by a Volt, whilst a horse-power is 746 Watts, and a Cheval de Vapeur 735. 1886 R. H. Thurston in Jrnl. Franklin Inst. Oct. 265 It was judged that it [sc. a dynamo] might have been driven up to 300,000 watts with safety. 1930 Engineering 21 Mar. 393/1 The panels are illuminated from behind by a standard 40-watt ‘pearl’ lamp. 1967 Canad. Med. Assoc. Jrnl. 7 Oct. 901/2 The patients exercised on a bicycle ergometer in a supine position at an energy level of 25 watts for 10 minutes. 2011 C. D. Ferguson Nucl. Energy: What Everyone needs to Know (e-book ed.) A light bulb powered by 100 watts requires delivery of 100 joules of electrical energy per second in order to light the bulb. 2. As a modifier (with preceding numeral or other adjective), designating something particularly attractive, striking, or powerful; usually esp. designating such a facial expression (typically a smile), as in ——watt grin, ——watt smile, etc. Π 1913 Electr. Worker Nov. 1137/2 Lovell faced the pitcher with a 30-watt smile. 1985 G. V. Higgins Penance for Jerry Kennedy viii. 67 He gave Dunn a six- or seven-hundred-watt glare. 2000 Edmonton (Alberta) Jrnl. (Nexis) 26 Nov. (Entertainment section) c4 The ex-Beatle has answered a private call to arms by lending his billion-watt celebrity to landmine elimination. 2016 Independent (Nexis) 24 Aug. 9 The nation is no stranger to the ten thousand watt grin of its most accomplished female boxer. Compounds watt-hour n. a unit of energy equal to that produced in one hour by a power of one watt (equal to 3600 joules); symbol Wh.Cf. kilowatt-hour n. at kilowatt n. Compounds. ΘΚΠ the world > matter > physics > energy or power of doing work > [noun] > specific quantities or units of energy or work horsepower1806 foot-pound1847 foot-ton1860 kilogrammetre1866 erg1873 kilerg1873 indicated horsepower1881 metre-ton1881 joule1882 watt-hour1888 manpower1893 horsepower-hour1899 horse1904 1883 Telegr. Jrnl. & Electr. Rev. 24 Feb. 166/1 If you are regarding the measure as 1,000 watt hours, it is not the same as 1,000 watts. 1907 E. Wilson & F. Lydall Electr. Traction I. 379 This can be converted into watt hours per ton mile thus. 2009 Daily Tel. 13 Jan. 13/2 A study has found that on average the wind turbines generate only 214 watt hours a day, less than five per cent of a household's daily electricity needs. watt-sec n. a unit of energy equal to that produced in one second by a power of one watt (equal to one joule); = watt-second n. ΘΚΠ the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > joule joule1882 coulomb-volt1893 watt-second1893 wattsec1962 1899 Electr. Rev. (U.S.) 7 Apr. 574/1 (table) Joules = watt-secs = 10⁷ ergs. 1962 New Scientist 18 Jan. 157/1 The term ‘wattsec’ is..a common one among radio engineers while ‘joule’ appears to be seldom used in practice. 2013 P. S. Auerbach Field Guide Wilderness Med. (ed. 4) iii. 38 If ventricular fibrillation or asystole is determined, defibrillate one time with 2 watt sec/kg up to 200 watt sec. watt-second n. a unit of energy equal to that produced in one second by a power of one watt (equal to one joule); symbol Ws. ΘΚΠ the world > matter > physics > electromagnetic radiation > electricity > electrical power, electricity > [noun] > joule joule1882 coulomb-volt1893 watt-second1893 wattsec1962 1886 Telegr. Jrnl. & Electr. Rev. 6 Aug. 154/1 I notice in your correspondence columns the expression, ‘number of foot-pounds in a watt’. It should be, ‘in a watt-second or joule’. 1981 Sci. Amer. Dec. 53/1 A photon with a frequency in the visible region of the electromagnetic spectrum has little energy: less than 10⁻¹⁹ joule, or watt-second. 2009 B. Stoppee & J. Stoppee Guide Photogr. & Light xiii. 384/2 Prepare to shell out a few dollars for the big 2,000 watt-second pack. This entry has been updated (OED Third Edition, December 2022). < n.1882
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