The term 'geometric prefix' refers to a set of words that are used to describe the number of sides or angles of a particular shape. The prefixes deca, TRI, octa, and tetra all refer to shapes with four, three, eight, and four sides respectively. Deca is derived from the Greek word for ten, TRI from the Greek word for three, octa from the Greek word for eight, and tetra from the Greek word for four. These prefixes are commonly used in mathematics and geometry to describe the properties of shapes.