The term that best describes a shape made of perfectly straight lines is a polygon.
A polygon is defined as a two-dimensional geometric figure that is formed by connecting a finite number of straight line segments. These segments are called sides, and they meet at points called vertices. Polygons can be classified into different categories based on the number of sides they have, such as triangles (three sides), quadrilaterals (four sides), pentagons (five sides), and so on. The key characteristic that sets polygons apart is that all of their sides are straight lines, which differentiates them from curves or rounded shapes.