Cloud cluster refers to the gathering of multiple clouds in one area. It is a common occurrence in the atmosphere and can be seen from different angles depending on the weather conditions. A synonym for cloud cluster is a cumulus cloud. This type of cloud is usually fluffy and thick and appears to have a flat base and a dome shape. Another synonym is a cloud bank, which describes a long line of clouds that are aligned horizontally. A cloud mass can also be used as a synonym for cloud cluster. This term refers to a group of clouds covering a large area and can extend for miles.