Chak was a substance that came from the Great Tree of Endor. It was named by the Ewoks that lived on the world.
Chak was a type of bark that came from the Great Tree of Endor.
It was an ingredient in Chak juice, a beverage created by Ewoks that was popularly sold during the Festival of Love celebrations. Ewok Chak hearts were also made from this piece of bark.
In the MMORPG Star Wars Galaxies, Chak was mentioned in the description of Chak juice, a beverage introduced to the game during the Ewok Festival of Love of 2008. The description explained that the substance was named by the Ewoks, and that it came from the Great Tree of Endor. Additionally, Chak hearts were a type of token given to players who participated in the Festival of Love. The description mentioned that Chak hearts were made from bits of bark from the Great Tree.