tornasole

Forms

tornasole m (countable and uncountable, plural tornasoli)^[1]

Etymology

It is from Italian tornare (“to turn”) + sole (“sun”), a verb–object compound like girasole, with the verb in its old sense “to turn round”.^{[2][3][4][1][5]} Zingarelli and Gabrielli see it as modelled on Ancient Greek ἡλιοτρόπιον (hēliotrópion, “heliotrope”).^[6][7]

Nocentini holds that French tournesol and Spanish tornasol come from the Italian word, while the GDLI derives the Italian word from them.^[8][9] Treccani leaves the question open because the dates of the Italian, French and Spanish forms are uncertain.^[4] DIFIT dates the French word in the sense “litmus” to 1360 and treats it as a partial calque.^[10]

The chemical sense comes from “sunflower” because the dye was originally extracted from that plant.^[11][12][4]

Earliest recorded meaning

The first record, with the sense “sunflower”, is in Dino Compagni (c. 1320), who compares something to quel tornasole che sempre le sue foglie gira with the turning of the sun.^[11][2][9] The TLIO's first record is Bosone da Gubbio (before 1333).^[3]

Semantic evolution

Lorenzo de' Medici calls tornasole a small flower known to the Latins as clytia.^[9] The name was also given to Chrozophora tinctoria, a Mediterranean plant whose dye, from red to blue, was used for cloth.^[2][4]

The sense “litmus”, a dye from lichens that turns red in acids and blue in alkalis, appears in 1599 in Ferrante Imperato.^[11] Its use as a chemical test gave cartina al tornasole, litmus paper, and figuratively a decisive test.^[12][13] In Tuscan the word also meant chicory (before 1756, Biscioni. 1863, Fanfani).^[11]

Timeline

• c. 1320 – Dino Compagni uses tornasole for the sunflower.^[11][2]
• Before 1333 – Bosone da Gubbio uses it.^[3]
• 1360 – French tournesol “litmus” is recorded.^[10]
• 1599 – Ferrante Imperato uses it for litmus.^[11]
• Before 1756 – Biscioni's Sienese vocabulary records the sense “chicory”.^[11]

Meanings

Noun

1. (chemistry) litmus: a dye from lichens, used as an indicator because it turns blue in alkaline and red in acid solutions: cartina al tornasole, litmus paper, and figuratively a decisive test.^[2][12][6]
2. (botany) turnsole (Chrozophora tinctoria), a Mediterranean plant that yields a red to blue dye.^[2][4][1]
3. (archaic) sunflower, the same as girasole.^[2][4][3]

Related words

• girasole
• eliotropio
• tornare
• sole
• French tournesol

Usage notes

The dye is also called laccamuffa.^[14][4] The dictionaries treat the noun as invariable.^[2][12]

References

1. ^ a b c d Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h De Mauro, Tullio (ed.) (2003), Grande dizionario italiano dell'uso, CD-ROM version 2.0, Torino: UTET
3. ^ a b c d Tesoro della Lingua Italiana delle Origini (1997–), Opera del Vocabolario Italiano, CNR, Firenze; tlio.ovi.cnr.it
4. ^ a b c d e f g Duro, Aldo (ed.) (1986–1994), Vocabolario della lingua italiana, Roma: Istituto della Enciclopedia Italiana; online ed. treccani.it/vocabolario (2008 copy)
5. ^ Devoto, Giacomo (1968), Avviamento alla etimologia italiana: dizionario etimologico, 2nd ed., Firenze: Le Monnier, p. 447
6. ^ a b Zingarelli, Nicola (2009), Lo Zingarelli 2010: vocabolario della lingua italiana, Bologna: Zanichelli
7. ^ Gabrielli, Aldo (2020), Grande dizionario italiano, digital ed., Milano: Hoepli
8. ^ Nocentini, Alberto; Parenti, Alessandro (2010), l'Etimologico: vocabolario della lingua italiana, Firenze: Le Monnier
9. ^ a b c Battaglia, Salvatore; Bàrberi Squarotti, Giorgio (1961–2002), Grande dizionario della lingua italiana, 21 vols., Torino: UTET; digital ed. Accademia della Crusca, p. 21
10. ^ a b Stammerjohann, Harro, et al. (2008), Dizionario di italianismi in francese, inglese, tedesco, Firenze: Accademia della Crusca; online at difit.italianisticaonline.it
11. ^ a b c d e f g Cortelazzo, Manlio; Zolli, Paolo (1999), Dizionario etimologico della lingua italiana, 2nd ed. by Manlio Cortelazzo and Michele A. Cortelazzo, Bologna: Zanichelli
12. ^ a b c d Devoto, Giacomo; Oli, Gian Carlo; Serianni, Luca; Trifone, Maurizio (2026), Nuovo Devoto–Oli: il vocabolario dell'italiano contemporaneo, digital ed., Milano: Le Monnier
13. ^ Vocabolario della lingua italiana Treccani (2011), Roma: Istituto della Enciclopedia Italiana
14. ^ Sabatini, Francesco; Coletti, Vittorio; Manfredini, Manuela (2026), Dizionario italiano Sabatini Coletti, digital ed., Milano: Sansoni / Rizzoli Larousse