heliotrope \HEE-lee-uh-trohp, noun:
1. A light tint of purple; reddish lavender.
2. Any hairy plant belonging to the genus Heliotropium, of the borage family, as H. arborescens, cultivated for its small, fragrant purple flowers.
3. Any of various other plants, as the valerian or the winter heliotrope.
4. Any plant that turns toward the sun.
5. Surveying. An arrangement of mirrors for reflecting sunlight from a distant point to an observation station.
But the heliotrope envelope with the feminine handwriting and the strange odor immediately suggested queries along lines of investigation which had never before entered her thoughts.
— George Gibbs, The Vagrant Duke
Blown by steady volumes of roaring wind, everyone’s hair is riffled and tangled and leaping in antic wisps, and the heliotrope robes bulk like tumors but flip up in sudden swoops.
— Edmund White, Forgetting Elena
Heliotrope literally meant “turn towards the sun” in Greek. Flowers that turned towards the sun became associated with this word.