radiant

Forms

radiant (feminine radiante, masculine plural radiants, feminine plural radiantes); in astronomy also a masculine noun radiant.^[1][2]

Etymology

It is borrowed from Latin radiāns (“radiating, shining”), the present participle of radiō (“to emit rays, shine”), which is from radius (“ray”).^[2][3][4] The Latin verb is also the source of radiation, and the Latin noun of rai and radieux.^[3] The English term radiant point is recorded from 1726, before the French use.^[2]

Earliest recorded meaning

It first appears as radians in the first half of the 13th century, in the Antéchrist of Berengier, meaning “radiant, shining”.^[2][3]

Semantic evolution

In the general sense “that radiates”, the word was displaced by rayonnant, which took that sense at the beginning of the 19th century; it survives only in literary use.^[3][2]

In the second half of the 19th century it passed into scientific language: in astronomy point radiant (1865) is the point of the sky from which the meteors of a shower seem to come, which gave rise to the noun radiant (1900 according to the TLFi, 1907 according to Rey and the GLLF).^[2][3][4] In physics it describes what is propagated by radiation (1880).^[3] The derivative radiance meant figurative radiance in 1825 and became a term of physics in the 20th century.^[2][3]

Timeline

• 1200–1250 – Radians “shining” in the Antéchrist of Berengier.^[2]
• 1726 – The English radiant point is recorded.^[2]
• Early 19th century – Rayonnant takes over the general sense.^[3]
• 1825 – The derivative radiance appears in Brillat-Savarin.^[2]
• 1865 – Point radiant is used in astronomy.^[2][3]
• 1880 – Used in physics of what spreads by radiation.^[3]
• 1900 – First use as a noun in astronomy.^[2]

Meanings

Adjective

1. (literary) That radiates or gives off light; shining.^[2][1]
2. (physics) Propagated by radiation: chaleur radiante, énergie radiante.^[2][4][1]
3. (astronomy) Point radiant: the point of the sky from which the paths of a meteor shower seem to come.^[2][1]

Noun

1. (astronomy) The radiant, the point from which the paths of a meteor shower seem to come.^[2][1][4]

Word family

• radiance

Related words

• rayonnant
• radieux
• radiation
• rai
• Latin radius

References

1. ^ a b c d e Rey-Debove, Josette; Rey, Alain, eds. (2007), Le Petit Robert de la langue française, Paris: Le Robert
2. ^ a b c d e f g h i j k l m n o p Trésor de la langue française informatisé (2004), ATILF – CNRS & Université de Lorraine, atilf.fr/tlfi; electronic version of Imbs, Paul; Quemada, Bernard, eds. (1971–1994), Trésor de la langue française, Paris: CNRS / Gallimard
3. ^ a b c d e f g h i j Rey, Alain, ed. (1992), Dictionnaire historique de la langue française, Paris: Le Robert
4. ^ a b c d Guilbert, Louis; Lagane, René; Niobey, Georges, eds. (1971–1978; 1989), Grand Larousse de la langue française, Paris: Larousse