The coconut is not actually a nut, and coconut trees are not really trees but actually a giant species of grass. For the Hindus however, the coconut was primarily a rare and perfect offering to the gods, containing pure water that was untouched by human hand.
Furthermore, the coconut's three "eyes" have philosophical significance, symbolising mankind's two physical eyes and the third eye of the conscience. Only this third eye can transcend superficiality and falsehood to perceive the ultimate truth.

A Gourmet's notebook