The word 'delta' originates from the Greek letter delta, named for its triangular shape. It was adopted into Latin and later English to describe the triangular landform at river mouths, notably the Nile delta.
A landform at the mouth of a river where it splits into several outlets, typically triangular in shape.
From the Greek letter 'delta' (Δ, δ), named for its triangular shape, used metaphorically to describe the triangular river delta. Key roots: δέλτα (Greek: "the letter delta, triangular shape").