turnsole

noun

turn·​sole

ˈtərnˌsōl

plural -s

1

: any of several plants whose flowers or stems are supposed to follow the movement of the sun:

a

: heliotrope sense 1b

b

: sunflower

c

: sun spurge

d

: a double-flowered tulip (Tulipa suaveolens) of southern Russia

2

: a European annual herb (Chrozophora tinctoria) of the family Euphorbiaceae the juice of which is turned blue by ammonia

3

a

: a purple dye obtained from the turnsole (see turnsole sense 2)

b

: litmus

Word History

Etymology

Middle English turnesole, from Middle French tournesol, from Old Italian tornasole, from tornare to turn (from Medieval Latin) + sole sun, from Latin sol (accusative solem)

The Ultimate Dictionary Awaits

Expand your vocabulary and dive deeper into language with Merriam-Webster Unabridged.

1. Expanded definitions
2. Detailed etymologies
3. Advanced search tools
4. All ad-free

Discover what makes Merriam-Webster Unabridged the essential choice for true word lovers.

Start Your Free Trial Now