Thunderhead is a term often used to describe a type of cloud that is known for producing thunderstorms. However, there are a number of different synonyms that can be used to describe this type of cloud. One common term is cumulonimbus, which is a type of cloud that is both tall and also dense. Other synonyms for thunderhead might include the terms thundercloud, storm cloud, or even just simply, a large cloud. Regardless of the word used to describe this type of cloud, it is typically associated with stormy weather and the threat of heavy rains, high winds, and lightning strikes.