The term 'River Area' can be summarized by the word 'DELTA', which is a five-letter word. A DELTA is an area of land that is formed at the mouth of a river, where the river splits into several smaller rivers or streams before emptying into an ocean, sea, or lake. Deltas are typically characterized by their triangular shape and are often rich in sediment deposits. They are also important habitats for many species of plants and animals.