Gold Open Access is literature that has an explicit open license, like CC-BY. It optionally has an article processing charge (APC). It optionally charges APC to make profit or to fund other activities, like some societies do. Green Open Access is literature that has been made available by repositories. It optionally has an open license. It optionally has a standardized license, like CC-BY. But it can also be that no clear license is given or the “license” refers to some (local) law.