heliotrope (n.) Look up heliotrope at Dictionary.com
"plant which turns its flowers and leaves to the sun," 1620s, from French héliotrope (14c., Old French eliotrope) and directly from Latin heliotropium, from Greek heliotropion "sundial; heliotropic plant," from helios "sun" (from PIE root *sawel- "the sun") + tropos "a turn, change" (from PIE root *trep- "to turn"). In English the word in Latin form was applied c. 1000-1600 to heliotropic plants. Related: Heliotropic.