Turnsole
Turnsole , noun
[French tournesol, Italian tornasole; tornare to turn (Late Latin tornare) + sole the sun, Latin sol. See Turn, Solar, a., and compare Heliotrope.]
1.
(a) (Botany) A plant of the genus Heliotropium; heliotrope; -- so named because its flowers are supposed to turn toward the sun.
(b)
(Botany) The sunflower.
(c)
(Botany) A kind of spurge (Euphorbia Helioscopia).
(d)
(Botany) The euphorbiaceous plant Chrozophora tinctoria.
2.
(a) (Chemistry) Litmus.
(b)
(Chemistry) A purple dye obtained from the plant turnsole. See def. 1 (d). [Obsolete]