Kachil is the Malayalam word for Greater Yam, Guyana Arrowroot, Ten-months Yam, Water Yam, White Yam, Winged Yam or Yam. Kachil is also known as Purple Yam.
Picture below is boiled Kachil called Kachil Puzhukku which is made from boiled bite-sized pieces of Kachil mixed with spices and of course curry-leaves and grated-coconut.