definition of heliotrope
The heliotrope is an instrument that uses a mirror to reflect sunlight over great distances to mark the positions of participants in a land survey. The heliotrope was invented in 1821 by the German mathematician Carl Friedrich Gauss. The word heliotrope is taken from the Greek: helios (Greek: á¼¥Î»Î¹Î¿Ï), meaning sun, and tropos (Greek: ÏÏÏÏÎ¿Ï), meaning turn. It is a fitting name for an instrument which can be turned to reflect the sun toward a given point.