Definition: The term "watercup" is a colloquial term used to describe a large, inflated balloon that resembles a cup. It can also refer to a small cup-shaped object in a person's hand or pocket. In literature and other contexts, the term "watercup" may be used to describe something that is very large and often filled with water. For example, it could be a large book or a large piece of art that is filled with water. The term "watercup" can