The term 'triangular area' can be represented by the word 'DELTA', which is a five-letter word. DELTA is a Greek letter that is often used to represent change in mathematics and science. In geometry, it is also used to refer to a triangular area or region. A DELTA is typically formed when a river splits into multiple branches before reaching the sea. The triangular shape of the DELTA is created by the sediment deposits from the river.