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).

• a plant that turns so that it faces the sun
  
• particularly, a purple-flowered plant of the species Heliotropium arborescens
       
• 1870, Benjamin Disraeli, Lothair
       
• :As they entered now, it seemed a blaze of roses and carnations, though one recognized in a moment the presence of the lily, the heliotrope, and the stock.
  
• (colour) a light purple or violet colour
       heliotrope colour:   
  
• the fragrance of heliotrope flowers
       
• 1881, Henry James, The Portrait of a Lady
       
• :... he had always smelt so much more of heliotrope than of gunpowder.
  
• a bloodstone (a variety of quartz)
  
• (colour) light purple or violet,
       
• 1904, Jerome K. Jerome, Tommy and Co.
       
• :Lady in a heliotrope dress with a lace collar, three flounces on the skirt?
       
• 1917, Zane Grey, Wildfire
       
• :And following that was a tortuous passage through a weird region of clay dunes, blue and violet and heliotrope and lavender, all worn smooth by rain and wind.
  
• keeping one's face turned toward the sun
       
• 1851, Herman Melville, Moby Dick
       
• :while still as on the night before, slouched Ahab stood fixed within his scuttle; his hid, heliotrope glance anticipatingly gone backward on its dial; sat due eastward for the earliest sun.