heliotrope

n. That which is hemitropal in construction; (Crystallog.) a twin crystal having a hemitropal structure. [ 1913 Webster ]

n. [ F. héliotrope, L. heliotropium, Gr. &unr_;; &unr_; the sun + &unr_; to turn, &unr_; turn. See Heliacal, Trope. ] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line. [ 1913 Webster ]

2. (Bot.) A plant of the genus Heliotropium; -- called also turnsole and girasole. Heliotropium Peruvianum is the commonly cultivated species with fragrant flowers. [ 1913 Webster ]

3. (Geodesy & Signal Service) An instrument for making signals to an observer at a distance, by means of the sun's rays thrown from a mirror. [ 1913 Webster ]

4. (Min.) See Bloodstone (a). [ 1913 Webster ]

Heliotrope purple, a grayish purple color. [ 1913 Webster ]