A net is a skeleton-outline of a solid that can be folded to make it.

Explanation:
A net is a two-dimensional representation of a three-dimensional object. It is a flat pattern that can be folded along its edges to form the solid shape it represents. Nets are commonly used in geometry to help visualize and understand the properties of various three-dimensional shapes.

Visualizing Nets:
To understand nets better, let's consider an example. Suppose we have a cube, which is a three-dimensional shape with six square faces. A net for a cube would consist of six squares connected by their edges, forming a cross-like pattern. Each square in the net represents one face of the cube.

If we cut out the net, fold it along the lines, and glue or tape the edges together, we can recreate the cube. The net provides a visual guide for assembling the solid shape accurately.

Importance of Nets:
Nets are essential in geometry because they help us understand the relationship between the faces, edges, and vertices of three-dimensional shapes. By examining nets, we can determine the number of faces, edges, and vertices a solid shape has.

Nets also allow us to explore the properties of various shapes and understand how they can be transformed. For example, by manipulating a net, we can see how a cube can transform into other shapes like a rectangular prism or a triangular prism.

Conclusion:
In conclusion, a net is a skeleton-outline of a solid shape that can be folded along its edges to recreate the three-dimensional object it represents. Nets are valuable tools in geometry that help us visualize and understand the properties of different shapes. They allow us to explore how shapes can be transformed and provide a visual guide for assembling solid objects accurately.