Light green and pear-shaped with a thick skin and a hard core, chayote, or sayote as it is called in the Philippines, grows on vines. It is known as as vegetable pear or mirliton in some parts of the world. In France, it is known as christophene. According to Gourmet Sleuth, chayote was first domesticated in Mexico.
Chayote grows abundantly in the Philippines and is, therefore, one of the cheapest vegetables available all-read round in markets. My kids are very fond of chayote and we use it for soup dishes. We even prefer using chayote over the traditional raw papaya when cooking tinola.