The term 'EIGHT AS A PREFIX' can be solved by the word OCTA, which is a four-letter word. Octa is a prefix meaning eight, and it is derived from the Greek word for eight, okto. It is commonly used in scientific and mathematical contexts to refer to objects with eight sides or components. For example, an octagon is an eight-sided shape, and an octahedron is a three-dimensional object with eight faces.