heliotrope
‘ancient sun-sun-dial’
Lexical development traced from the Tamil root:
E. eliotropus, elitropium, elitropius, helytropium, heliotropion < F. heliotrope < O.F. eliotrope < Lat. heliotropium < Gk. hēliotropion ‘sundial; heliotropic plant’ < hēlios ‘sun’ + tropos ‘a turn, change’ < heel < sawel- < Tamil el