\He"li*o*trope\, n. [F. h['e]liotrope, 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.