Young Coconut
When the coconut is still green, the endosperm inside is thin and tender, often eaten as a snack. But the main reason to pick the nut at this stage is to drink its water; a big nut contains up to one liter.
The meat (white flesh seen here) in a young coconut is softer and more like gelatin than a mature coconut, so much so, that it is sometimes known as coconut jelly.
When the nut has ripened and the outer husk has turned brown, a few months later, it will fall from the palm of its own accord.