Koʻolau means windward — a very appropriate name for a mountain range that runs up the windward side of the island of Oʻahu. It can be used as an adjective too, to describe something that is on the windward side.
Koko means blood. It took on a special meaning when blood quantum was used by the U.S. government as a way to decide which Hawaiians would receive benefits and which ones would not.