a European plant, Chrozophora tinctoria, of the spurge family, yielding a purple dye.
4.
the purple dye prepared from this plant; litmus.
Origin: 1325–75; ME turnesole < MF tournesol the dye < It tornasole the plant, lit., (it) turns (toward the) sun, on the model of Gk hēliotrópionheliotrope
Any of several plants of the genus Heliotropium, especially H. arborescens, native to Peru and having small, highly fragrant purplish flowers. Also called turnsole.
A moderate, light, or brilliant violet to moderate or deep reddish purple.
[Middle English elitrope (from Old English eliotropus) and French héliotrope, both from Latin hēliotropium, from Greek hēliotropion : hēlio-, helio- + tropos, turn; see trope.] he'li·o·trope' adj.
turn·sole (tûrn'sōl') n.
Any of various plants that move or are believed to move in response to the sun.
[Middle English turnesole, purple dye obtained from the plant, from Old French tournesol, from Old Italian tornasole, heliotrope : tornare, to turn (from Latin tornāre; see turn) + sole, sun (from Latin sōl; see sāwel- in Indo-European roots).]
[turn-sohl] 
