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1. Any of various plants that move or are believed to move in response to the sun, especially the Mediterranean species Chrozophora tinctoria.

[Middle English turnesole, dye made from C. tinctoria, from Old French tournesol, from Old Italian tornasole : tornare, to turn (from Latin tornāre; see turn) + sole, sun (from Latin sōl; see sāwel- in Indo-European roots).]
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.


1. (Plants) any of various plants having flowers that are said to turn towards the sun
2. (Plants) a euphorbiaceous plant, Croton tinctoria, of the Mediterranean region that yields a purple dye
3. (Dyeing) the dye extracted from this plant
[C14: from Old French tournesole, from Old Italian tornasole, from tornare to turn + sole sun, from Latin sōl sun]
Collins English Dictionary – Complete and Unabridged, 12th Edition 2014 © HarperCollins Publishers 1991, 1994, 1998, 2000, 2003, 2006, 2007, 2009, 2011, 2014



1. any of several plants regarded as turning with the movement of the sun.
2. a European plant, Chrozophora tinctoria, of the spurge family, yielding a purple dye.
3. the dye itself; litmus.
[1325–75; Middle English turnesole < Middle French tournesol < Italian tornasole, literally, (it) turns (toward the) sun, on the model of Greek hēliotrópion heliotrope]
Random House Kernerman Webster's College Dictionary, © 2010 K Dictionaries Ltd. Copyright 2005, 1997, 1991 by Random House, Inc. All rights reserved.
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References in periodicals archive ?
The reflectance spectrum shows two absorption bands at 540 nm and 580 nm (Figure 6(a)) that could be related to the presence of folium (or turnsole), a colorant produced by Chrozophora tinctoria plant, widely used on manuscripts [42].
Following the week-long visit to PROINSO's HQ in the UK, with a 2-day complementary training session on PROINSO PV Rack, TURNSOLE and SMA's inverter and energy storage solutions, Electric Solar and PROINSO have agreed to add a 4MW joint pipeline for Honduras in 2017; setting the ground for a long-term partnership between the two companies.
It is identified as dyer's croton, giradol, or turnsole and is inhabitant to Africa, tropical Asia, and Europe [9].
Look at the variety of both abstract and concrete entities, which carry Old Sol's name (5): An element (Helium), a body part (solar plexus), a geographical area (the Sun Belt of the United States), several plants (e.g., Helianthus annuity or the sunflower, heliotrope, also known as turnsole, and Helenium or sneeze-weed, also called swamp sunflower), and a North American Indian ceremony (sun dance); the latter first became the source of the name of a small town in Wyoming (Sundance with a population of 1182), then of Harry Alonzo Longabaugh's nickname (the Sundance Kid, for having stolen a horse there in 1887).
Red came from sandalwood, purple from turnsole, a Mediterranean plant, and black from boiled blood.