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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.
2. See heliotrope.
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]
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]