Which of the following refers to the open end of an oblong?

The term that refers to the open end of an oblong is concave. In hairstyling and design, understanding shapes and their properties is crucial. An oblong is essentially a rectangle that is longer than it is wide. The open end refers to the part that curves inward, creating a space that lacks a solid boundary. This inward curve is what is described as concave.

In context, the concave aspect of an oblong shape is important in hairstyling for creating movements and styles that enhance the natural shape of the head and features. Recognizing concave and convex shapes helps ascertain how to manipulate hair into desired forms, as these shapes influence how light interacts with hair, providing texture and volume in styles.

While convex refers to surfaces that bulge outward, flat describes a level surface without elevation changes. Edge may suggest a sharp or defined boundary. However, none of these terms align with the specific description of the open end of an oblong, making concave the accurate choice to describe this characteristic.