He″li‐o‐trope (?), n. [F. héliotrope, L. heliotropium, Gr. �; � the sun + � to turn, � turn. See Heliacal, Trope.] 1. (Anc. Astron.) An instrument or machine for showing when the sun arrived at the tropics and equinoctial line.
2. (Bot.) A plant of the genus Heliotropium; — called also turnsole and girasole. H. Peruvianum is the commonly cultivated species with fragrant flowers.
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.
4. (Min.) See Bloodstone (a).
Heliotrope purple, a grayish purple color.