[turn.sole] n [ME turnesole, fr. MF tournesol, fr. OIt tornasole, fr. tornare to turn (fr. ML) + sole sun, fr. L sol--more at turn, solar] (14c) 1: a European herb (Chrozophora tinctoria) of the spurge family with juice that is turned blue by ammonia; also: a purple dye obtained from it
2: heliotrope 1