α. late Middle English–1600s radyant, 1500s radiaunt, 1500s radyaunt, 1500s radyaunte, 1500s– radiant, 1600s readiant.
β. late Middle English–1500s radyent, 1600s– radient (now nonstandard).
radiantadj.n.
/ˈreɪdɪənt/, U.S. /ˈreɪdiənt/ A. adj.
1.
a. Sending out rays of light; shining brightly. Also figurative.
ΘΚΠ
the world > matter > light > [adjective] > emitting rays
beamy1398
flaming?a1400
streaminga1400
radious1417
radiantc1450
beamed1480
irradiant1526
beamish1530
beamsome1595
beamfula1631
irradiating1651
radiating1651
beaming1667
streamy1718
irradiativea1834
radiescent1863
emissive1870
c1450 in Archiv f. das Studium der Neueren Sprachen (1913) 131 61 (MED) Blissede be þi browes..Silke thredys twynede, gilted most heuenliture, Gay, radyant, to þam may likenede bee.
?a1475 Ludus Coventriae (1922) 358 Heyl radyant sterre; the sunne is not so bryth.
c1510 Gesta Romanorum Add. Stories ii. 433 [Christ's] body yt was..more radyent than ony syluer.
1577 J. Grange Golden Aphroditis sig. D.iv Wherefore (thou radyant Starre) seyng an easye conqueste requireth the Conqueroures clemencye, [etc.]
1600 W. Shakespeare Midsummer Night's Dream iii. i. 87 Most radiant Pyramus, most lillie white of hewe.
1604 M. Drayton Owle sig. Gv The great Eagle..Which from the mountaine (with a radient eye) Brau'd the bright Cressit of the glorious skye.
1667 J. Milton Paradise Lost iii. 63 On his right The radiant image of his Glory sat, His onely Son. View more context for this quotation
1725 A. Pope tr. Homer Odyssey II. v. 354 Far on the left those radiant fires to keep The Nymph directed, as he sail'd the deep.
1743 E. Young Complaint: Night the Fourth 23 This gloom of Night,..With all her radiant Worlds.
1812 J. Wilson Isle of Palms ii. 493 Her little sail beneath the sun Gleams radiant as the snow.
1838 R. W. Emerson Lit. Ethics in Wks. (Bohn) II. 208 The humblest..in view of these radiant facts, may now theorize and hope.
1872 J. S. Blackie Lays of Highlands 75 The height which bears The sailor's radiant mark.
1920 F. S. Fitzgerald This Side of Paradise ii. v. 305 He stretched out his arms to the crystalline, radiant sky.
1961 Times 27 Sept. 10/3 The radiant sun of durable peace should shine over mankind.
1997 J. Hatfield & G. Burt Unauthorized X-Cycl. 112 A radiant effulgence created by disintegrating timber was believed..to be the spirits of massacred Indians.
b. Of the eyes, a look, etc.: bright or beaming (as with joy or love). Of a person, esp. a young woman or bride: giving off an aura of joyfulness or health; glowingly happy. In earlier quots., esp. those relating to eyes, with admixture of sense A. 1a.
ΘΚΠ
the mind > emotion > pleasure > joy, gladness, or delight > [adjective] > expressive of joy (of looks or actions) > beaming with joy
bright1559
radiant1589
rayonnant1825
beaming1832
1589 T. Lodge Scillaes Metamorphosis sig. Bv It was my chaunce..to spie a Nimph of such a radiant glancing.
a1631 J. Donne Poems (1633) 131 May never age, or error overthwart With any West, these radiant eyes, with any North, this heart.
1690 T. Shadwell Amorous Bigotte iv. i. 37 I am so dazled with your radiant Eye.
1722 E. Thomas Misc. Poems 52 Celestial Faith, her welcome Change did bless, and radiant Smiles, declar'd her Happiness.
1794 R. Burns Poems & Songs (1968) III. 747 The glorious sun..Out-rivall'd by the radiant eyes Of..charming Chloe.
1814 W. Wordsworth Excursion viii. 381 From the rocky garden mount..descends..a radiant Girl, For she hath recognized her honoured Friend, The Wanderer ever welcome!
1859 N. Hawthorne Fr. & Ital. Jrnls. II. 287 The most radiant eye that the dull earth ever opened to see heaven withal.
1898 R. S. Hichens Londoners vi. 93 He glanced again at the radiant Huskinson, now in animated conversation with Lady Pearl.
1925 F. S. Fitzgerald Great Gatsby vi. 132 Perhaps some unbelievable guest would arrive, a person infinitely rare and to be marvelled at, some authentically radiant young girl.
1967 T. Wilder Eighth Day i. 85 The Princess of Trebizond gave him her hand, a radiant smile, and tripped upstairs.
1986 Los Angeles Times 31 Aug. vi. 12/5 The intended result is to have the deb look as radiant as a bride, but still innocent and sweet.
2005 M. David Slow down Diet vii. 155 Have you ever met someone who..became ‘born again’ in his or her body and is now more vibrantly alive, radiant, happy, and inspired?
c. Of an object or image: represented as sending out rays of light, or having radial projections resembling such rays; (Heraldry) = rayonné adj.
ΘΚΠ
the world > matter > light > [adjective] > emitting rays > represented as having or sending out
radiant1614
radiated1655
radiate1757
society > communication > indication > insignia > heraldic devices collective > representations of articles of clothing > [adjective] > crowned or coroneted > radiant (of crown)
radiant1614
radiated1655
1614 J. Selden Titles of Honor 138 Which the learned Paschalius interprets for a Crown radiant.
1661 S. Morgan Sphere of Gentry iv. vi. 83 A kind of radiant or pointed Coronet.
1729 J. Martyn 1st Lect. Bot. 19 In form of a radiant Star.
1780 J. Edmondson Compl. Body Heraldry II. (Gloss.) Radiant, Rayonned..terms used to express any ordinary edged with glittering rays, or shining beams.
1799 tr. Laboratory (ed. 6) II. i. 16 The radiant crown, on ancient coin, signifies that the prince was..Deified.
1863 Harper's Mag. Jan. 168/1 He took a tablet and drew on it a figure of a radiant sun, with the name Jesus indicated in the centre by the monogram I.H.S.
1894 H. Gough & J. Parker Gloss. Terms Heraldry (new ed.) 491 Azure, on a pale radiant or, a lion rampant gules.
1910 Amer. Jrnl. Archaeol. 14 386 A youth wearing a radiant crown approaches on a winged horse.
1977 Art Jrnl. 36 274/1 In examining the statue's face, Trachtenberg discusses the radiant crown which adds an aura of beatitude.
2005 Independent (Nexis) 2 May 44 You get an edge that's serrated, or viscous, or radiant, or spongy, or frilly.
2. † a. Of (esp. solar) heat: strong, fierce. Obsolete.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > [adjective] > intense or strong
keen1340
radiant1508
rigorous1630
1508 J. Fisher Treat. Penyt. Psalmes sig. xx.vi Ionas..made hym a shadowynge place for his defence agaynst the radyaunte heet of the sonne.
1633 W. Lithgow Scotlands Welcome sig. G3 Twixt Thy Heart and Soule, two Tropicks great, I vnder-plac'd, may find Thy radiant heat.
1672 J. Evelyn tr. R. Rapin Of Gardens ii. 75 His [sc. the Sun's] radiant heat Should on your house through various windows beat.
1707 J. Mortimer Whole Art Husbandry xiii. 292 The Sun may lend His influence from the East; his radiant heat, Should on your House thro' various Windows beat.
1782 Literary Amusements I. 78 The rising sun—the radiant heat of noon, the mild beams of the same great luminary, with the last departing gleam of the grey twilight.
1862 E. Stoddard Morgesons xli. 256 Neither bird nor insect chirped; they were hid from the radiant heat in tree and sod.
b. Of light: issuing or appearing in the form of rays; shining, splendid, dazzling. Also figurative (of beauty, qualities, etc.): shining or projected outward like rays of light.
ΘΚΠ
the world > matter > light > [adjective] > emitting rays > of the nature of or resembling rays
radiant1509
radial1570
radious1692
streamy1718
beam-like1820
actinomorphous1879
the mind > attention and judgement > beauty > splendour > [adjective] > radiant
shininga900
gladOE
steepa1000
lightsomea1382
freshlyc1426
prefulgentc1480
flagrant?a1500
radiant1509
glazed?1510
refulgent1528
bright-headeda1560
shone1595
tinsel1595
skinkling1790
epiphanous1823
foudroyant1860
1509 S. Hawes Pastyme of Pleasure (de Worde) xxv. sig. J.viiiv The mone..is fayre resplendysshaunt In the longe nyght with rayes radyante.
1517 S. Hawes Pastime of Pleasure (1928) iii. 18 The radyant bryghtnes of golden Phebus.
1548 N. Udall et al. tr. Erasmus Paraphr. Newe Test. I. Pref. f. C ijv The clere radiaunt sunnebeames of his holy woorde.
a1616 W. Shakespeare Twelfth Night (1623) i. v. 163 Most radiant, exquisite, and vnmatchable beautie. View more context for this quotation
1646 Sir T. Browne Pseudodoxia Epidemica v. ix. 247 With scintillations, or radiant Halo's about their head. View more context for this quotation
1688 J. Barker Poet. Recreations ii. 11 Bright Chrysolites, and Stones of Jasper, Make but a poor Resemblance of this light, Whose gilt and radiant Beams appear too bright.
c1750 W. Shenstone Elegies ix. 28 All that bears the radiant stamp of Kings.
1781 W. Cowper Truth 61 Meridian sunbeams tempt him to unfold His radiant glories.
1810 G. Crabbe Borough i. 9 Velvet Leaf with radiant beauty drest.
1878 M. A. Brown tr. J. L. Runeberg Nadeschda 66 A radiant glow o'erspread Her rigid face.
1922 J. Joyce Ulysses i. i. [Telemachus] 6 He swept the mirror a half circle in the air to flash the tidings abroad in sunlight now radiant on the sea.
1989 S. Holbeche Power Gems & Crystals i. 6 When I..had an NDE..I simply found myself out of my body, being drawn through a circle of radiant white light..into a tunnel-like space.
2002 Nature Photographer Summer 22/1 Southwest slot canyons where radiant streaks of midday sun suddenly penetrate cracks high above your head.
3. Botany. Extending outwards from a common centre; having parts that extend in this way. Also: having outer florets that differ from the inner ones; having ray florets. Cf. radiate adj. 1a. Now rare.
ΘΚΠ
the world > plants > part of plant > (defined by) distribution, arrangement, or position > [adjective] > arranged in a radiating manner
spoky1551
beamy1562
radiated1665
radiate1668
radiant1737
1737 P. Miller Gardeners Dict. (ed. 3) at Gallium The Leaves..are produc'd at the Joints of the Stalks, five or six in Number, in a radiant Form.
1789 tr. C. Linnaeus Syst. Veg. II. 629 Pectis. Receptacle naked... Radiant florets.
1830 J. Lindley Introd. Nat. Syst. Bot. 153 The radiant stigma of Papaver.
1836 J. C. Loudon Encycl. Plants (rev. ed.) 1103/2 Radiant, or Radiate, a flower is said to be radiant, when, in a cluster or head of florets, those of the circumference or ray are long and spreading, and unlike those of the disk.
1847 W. E. Steele Handbk. Field Bot. 34 Pet[als] obcordate, the outer ones radiant and deeply bifid.
1901 J. Muir Our National Parks iv. 111 The leaves are about three or four inches long, in clusters of five, finely tempered, bright lively green, and radiant.
1922 Bot. Exchange Club, Rep. for 1921 407 The property of producing radiant marginal florets seems inherent in the genus [sc. Centaurea] and is, no doubt, a latent character in the group of nigra.
1958 Ann. Missouri Bot. Garden 45 2 Early Spanish missionaries to the New World saw in the radiant flowers of Passiflora a symbol of the Crucifixion.
4.
a. Of heat: transmitted by radiation, rather than by convection or conduction.The radiation is now identified with electromagnetic radiation in the infrared part of the spectrum.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > [adjective] > radiant
radiant1780
the world > matter > physics > electromagnetic radiation > heat > [adjective] > radiation
radiative1759
radiant1780
1780 J. R. Forster tr. K. W. Scheele Chem. Observ. & Exper. on Air & Fire 74 The heat darting from this hillock all around, is that which may be reflected by a polished metal plate; that on the contrary which rises upwards, and may be driven by winds to and fro, unites with Air. I will call the first kind, for distinction sake, radiant heat.
1800 W. Herschel in Philos. Trans. (Royal Soc.) 90 291 If we call light, those rays which illuminate objects, and radiant heat, those which heat bodies, it may be inquired, whether light be essentially different from radiant heat?
1806 W. Henry Epitome Chem. (ed. 4) i. iii. 27 Radiant Caloric exhibits several interesting properties.
1869 E. A. Parkes Man. Pract. Hygiene (ed. 3) 309 Radiant heat from an open fire.
1871 B. Stewart Heat (ed. 2) §398 Instruments for measuring the intensity of the sun's radiant heat have been devised.
1922 Gas Manuf., Distribution & Use (Brit. Commerc. Gas Assoc.) ii. 113/1 The fire-clay material when so heated emits radiant heat which is rapidly transferred through the tubes to the water.
1983 J. S. Foster Struct. & Fabric (rev. ed.) I. iii. 224/1 The fireback sloping forward to direct radiant heat into the room.
2005 M. Bjornerud Reading Rocks iv. 106 In the frigid hinterlands of the solar system, far from the radiant heat of the Sun, the solid forms of water, carbon dioxide, and methane could persist.
b. Designed to emit radiant heat, esp. for cooking or heating.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > heating or making hot > [adjective] > sending out radiant heat
radiant1917
1917 Times 23 Aug. 3/2 An electric radiant heater is used to maintain the necessary temperature.
1936 Faber & Kells Heating & Air-conditioning iv. 81 The warming effect of convectors is slower than with the radiant type of heater.
1951 Good Housek. Home Encycl. 35/2 More recently the use of ‘radiant radiators’..has become more common.
1957 Heating, Ventilating, Air Conditioning Guide 35 399 Radiant heaters..have a refractory directly above the burners which is heated to incandescence.
1987 A. Tull Food & Nutrition (ed. 2) v. 252/2 The most familiar type of hotplate is the radiant ring.
1993 Collins Compl. DIY Man. (new ed.) ix. 407/1 Some gas and solid-fuel boilers can be fitted as a ‘back boiler’ behind a radiant fire or room heater.
5. Characterized by divergence of lines or rays from a central point or region. Now rare.
ΘΚΠ
the world > space > relative position > inclination > divergence > [adjective] > characterized by radial divergence
radiant1799
radiating1801
radiatory1816
1799 A. Walker Syst. Familiar Philos. ii. 45 The filings will leave their radiant direction and catch hold of filings of the opposite poles.
1825 ‘J. Nicholson’ Operative Mechanic 406 Cut into grooves,..in a radiant direction from the centre.
1851 J. Ruskin Stones of Venice I. xx. 223 The scallop also is a pretty radiant form.
1881 Nature 17 Mar. 462 A means..for carrying energy in a ‘radiant’ manner (i.e. in the direction of the rays of light from a point) in all directions.
1957 Vigiliae Christianae 11 86 The radiant flutings are not modelled from the curved or rounded ribs of a scallop shell.
2000 Garden Hist. 28 274 From the apse, three pathways diverge in a symmetrical radiant pattern.
2006 ‘L. Burana’ Try ii. 16 Deep crow's feet ran in radiant lines to his cheeks.
B. n.† 2. Geometry. A straight line drawn from a fixed point about which it can revolve, sweeping out a curve or surface. Obsolete.
1.
a. Physics. A point, or a small region or object, from which light or heat radiates; a substance or object emitting radiation. Now rare.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > [noun] > radiation of heat > point or object radiating heat
radiant1728
the world > matter > physics > electromagnetic radiation > light > emission of light, radiation > [noun] > point from which rays proceed
radiant point1665
focus1704
focal point1713
radiant1728
radiator1811
point source1894
1728 E. Chambers Cycl. at Radiant-Point All the Rays proceeding from the same Radiant continually diverge... Every Ray carries with it the Species, or Image of the Radiant.
1800 Philos. Trans. (Royal Soc.) 90 295 Our next division comprehends the heat of coloured radiants.
1869 J. Tyndall Notes 9 Lect. on Light §291 All bodies, whether luminous or non-luminous, are radiants; if they do not radiate light they radiate heat.
1926 U.S. Patent 1,574,547 2/1 Stefan's law..makes the total amount of radiation proportional to the fourth power of the absolute temperature of the radiant.
b. Each of the heating units or elements in a radiant heater.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > heating or making hot > that which or one who heats > [noun] > a device for heating or warming > devices for heating buildings, rooms, etc. > gas or electric heater > heating element of electric fire
radiant1914
bar1926
1914 Rep. Brit. Assoc. Advancem. Sci. 1913 436 A little later a more marked step in the evolution of the new radiating fire consisted in joining the two or three fireclay pieces into one, and thus making the firefront consist of a series of hollow fireclay columns (now known as radiants).
1936 Economist 28 Mar. 738/1 Our ‘Thermo-XX Beam’ radiant..was the first radiant designed to emit an increased proportion of short infra-red rays.
1953 ‘N. Shute’ In Wet 173 They sat down in arm chairs before the radiants of the electric fire.
1985 Times 15 Mar. 22/6 The radiants for conventional gas fires are produced in gas-fired kilns.
2006 Macon (Georgia) Tel. (Nexis) 17 Nov. The ceramic heating radiants must be in good shape.
ΘΚΠ
the world > relative properties > number > geometry > line > [noun] > other
medial line1570
radius1590
lineature1630
foot line1658
rectification1685
axis1734
slant side1824
radiant1842
transverse1867
median1883
bilinear1923
1842 W. T. Brande Dict. Sci., Lit. & Art 1012/1 The theory of the description of lines of the second order by the intersection of radiants is given by Newton in the Principia.
1846 in L. Campbell & W. Garnett Life J. C. Maxwell (1882) 77 r and r′ being the radients to any point of the curve from the two foci.
3. Astronomy. The point or small region of the sky from which the meteors in a meteor shower appear to diverge; a radiant point.
ΘΚΠ
the world > the universe > constellation > comet or meteor > meteor > [noun] > shower > focal point of
radiant1864
radiant point1864
1864 Brit. Assoc. Rep. Meteors (1865) 101 Professor Heis..has..divided his meteor-showers and radiants into bi-monthly divisions.
1884 Athenæum 20 Dec. 809/3 The meteors from some radiants leave a streak; those from others are swift.
1926 H. N. Russell et al. Astron. I. xiii. 457 Some of the radiants, notably that of the Perseids, are about equally active every year.
1996 Guardian 9 Dec. ii. 38/2 Close to Castor is the radiant of this week's Geminids meteor shower.
Compounds
radiant efficiency n. the ratio of the radiant flux emitted by something to the power it consumes.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > heat > [noun] > emission or diffusion > energy produced by > as flow > efficiency of
radiant efficiency1901
1901 Science 19 July 109/1 The Radiant Efficiency of Vacuum Tubes.
1914 Rep. Brit. Assoc. Advancem. Sci. 1913 435 The true remedy must be sought for in increasing the ‘radiant efficiency’ of the [gas] fire.
1936 Faber & Kells Heating & Air-conditioning iv. 74 Their [sc. gas fires'] radiant efficiency is about 50 per cent. (with an additional 10 per cent. convection).
2000 C. E. Baukal Heat Transfer Industr. Combustion viii. 310 The burner was reported to have a radiant efficiency of 80%, compared to an efficiency of 40% for conventional high-temperature burners.
radiant energy n. energy in the form of radiation, esp. electromagnetic radiation.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > heat > [noun] > emission or diffusion > energy produced by
radiant heat1626
radiant heating1825
radiant energy1869
1869 C. F. Winslow Force & Nature 400 Some exhaustless radiant energy has been constantly, though paradoxically, insisted upon as necessary to enable our central orb to diffuse his rays so far and potently.
1914 Rep. Brit. Assoc. Advancem. Sci. 1913 436 Part of the radiant energy is directly determined..by using a radiation calorimeter.
1970 M. V. Klein Optics iv. 121 The radiant energy density..is the radiant energy contained in a unit volume of space.
1989 S. H. Schneider Global Warming (1990) ii. 16 Because the earth has temperature, it emits radiant energy known as thermal radiation or planetary infrared radiation.
radiant flux n. a flux of radiant energy; (Physics) the rate of flow of radiant energy.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > heat > [noun] > emission or diffusion > energy produced by > as flow
flux1863
radiant power1863
radiant flux1896
radiance1917
1896 Science 17 July 78/2 The radiant flux of energy from the sun is W = V.EH.
1917 Astrophysical Jrnl. 45 44 Through this space radiant energy is passing at a certain rate. This rate constitutes the radiant flux through the space.
1944 Jrnl. Optical Soc. Amer. 34 252/2 When radiant flux is evaluated with respect to its capacity to evoke the brightness attribute of visual sensation it is called luminous flux.
1994 R. G. Fleagle Global Environmental Change ii. 23 To understand the effect of adding one or more greenhouse gases to the atmosphere, it is useful to visualize the normal radiant fluxes passing through the top of the atmosphere.
radiant heating n. heating of a room or area by means of radiant heat; frequently attributive.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > heat > [noun] > emission or diffusion > energy produced by
radiant heat1626
radiant heating1825
radiant energy1869
the world > matter > properties of materials > temperature > heat > heating or making hot > [noun] > heating of building > specific system of
radiant heating1825
central heating1871
baseboard heating1908
pressure jet1910
space heating1930
ondol1935
gas firing1961
storage heating1961
microbore1968
1825 Philos. Trans. (Royal Soc.) 115 187 (title) An experimental enquiry into the nature of the radiant heating effects from terrestrial sources.
1912 Cassier's Mag. 41 570/1 The demonstrations were continued..at the experimental works of the Radiant Heating Syndicate.
1966 McGraw-Hill Encycl. Sci. & Technol. (rev. ed.) XI. 213/1 Any radiant-heating system using a fluid heat conveyor may be employed as a cooling system by substituting cold water or other cold fluid.
1982 P. Wayburn Adventuring in Alaska ii. 90 Most of the ferries have a solarium or sundeck, where there are deck chairs and a radiant heating system that keeps you cosy even in frigid weather.
2006 Banff Crag & Canyon (Nexis) 28 Nov. 23 The Canmore Hotel plans to build a fenced outdoor area complete with radiant heating below the existing patio.
radiant-heated adj. heated by means of radiant heat.
ΘΚΠ
the world > matter > properties of materials > temperature > heat > heating or making hot > heat or make hot [verb (transitive)] > prior to use or treatment
preheat1862
radiant-heated1937
1937 Charleston (W. Va.) Daily Mail 17 Oct. 4/6 (heading) Advantages of Century's Radiant Heated Oven.
1962 Punch 24 Jan. 178/2 The ‘tropical radiant-heated indoor pool’.
2001 N.Y. Times Mag. 5 Aug. 46 (caption) The living room..has radiant-heated concrete floors.
radiant point n. a central point from which lines or rays diverge; (Astronomy) the radiant (sense B. 3) of a meteor shower.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > light > emission of light, radiation > [noun] > point from which rays proceed
radiant point1665
focus1704
focal point1713
radiant1728
radiator1811
point source1894
the world > the universe > constellation > comet or meteor > meteor > [noun] > shower > focal point of
radiant1864
radiant point1864
1665 R. Hooke Micrographia lix. 241 For the discovery of small Stars, the bigger the aperture be, the better adapted is the Glass;..by that means, uniting more Rays very near to one point, it does make many of those radiant points conspicuous.
1737 J. Rowning Nat. Philos. iii. 34 Let the Distance of the radiant Point be 20, and the Radius of Convexity be 5.
1833 N. Arnott Elements Physics (ed. 5) II. 209 If the distance of the radiant point be very great, they [sc. the rays] really are..nearly parallel.
1864 A. S. Herschel in Monthly Notices Royal Astron. Soc. (1865) 33 Two radiant-points of shooting stars..presented themselves in Auriga and in Cetus.
1907 Amer. Math. Monthly 14 64 The resulting four triangles..will be commonly co-polar in the radiant point O.
1991 C. A. Ronan Nat. Hist. Universe 146/1 Thus there are the Perseids with their radiant point in Perseus, the Leonids with a radiant in Leo, and so on.
radiant power n. the ability to radiate heat, or light; (Physics) the power of radiated energy; spec. = radiant flux n.
ΘΚΠ
the world > matter > physics > electromagnetic radiation > heat > [noun] > emission or diffusion > energy produced by > as flow
flux1863
radiant power1863
radiant flux1896
radiance1917
1863 E. L. Youmans Class-bk. Chem. 142 If the metal is covered with woollen or velvet, its radiant power is increased.
1864 Philos. Trans. (Royal Soc.) 154 368 The radiant power of the salt is little more than one-third that of the glass.
1923 Sci. Papers U.S. Bureau of Standards No. 475. 132 The ratio of luminosity to radiant power—the luminous efficiency.
1932 A. C. Hardy & F. H. Perrin Princ. Optics i. 19 If the human eye were uniformly sensitive to radiation of all wave lengths, the radiant power expressed in watts would provide an adequate method of evaluating the flux.
2003 Proc. National Acad. Sci. U.S.A. 100 6282/1 The first step of the analysis was to multiply the figures..by the spectral radiant power distribution of D65 light.
ΚΠ
1841 Trans. Amer. Philos. Soc. 7 267 A radiant region, if not a radiant point, was soon perceivable. The paths traced back..passed through a circle..with a radius of 2°.
1899 Science 6 Jan. 37/1 The discovery of this comet..on the radiant region of the Leonids, is the most interesting episode of the meteor observations.
This entry has been updated (OED Third Edition, June 2008; most recently modified version published online June 2022).
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adj.n.c1450