Growing up in India, this question never crossed my mind, until a dear friend asked me what it was when she had sheer kurma at my place. Charoli is often found in some Indian desserts like sheer kurma, phirnis, kheers to name a few. At times it is also used to add flavor and to thicken sauces, like in some meat stews or kurmas . Charoli has a nutty flavor and the inside part of the nut almost taste like pine nuts and the outside part like a pistachio. Size wise, it is smaller then a pea.
picture courtesy : Gardinita.net
Charoli's scientific name is Buchanania Lanzan. It is a perennial and comes from a small ever green tree, around 15 meters or so. Its bark is grey/black in color. The hard shell is cracked and the kernel inside the fruit is what Charoli is. The tiny seeds are dried are cultivated mainly in northwest parts of India.
Charoli is not only used for flavoring and or garnishing indian sweets, but it also has many medicinal benefits, it is used in Ayuerveda and Unani system of medicine. In Ayuerveda it is used to cure blood disorders, fevers, thirst, ulcers, etc. In Unani medicine it is used for digestive, thirst, blood purification,expectorant, purgative etc. It is also an aphrodisiac.