Name one solid according to its description: the figure has one base that is an octagon.

One solid that matches the given description is an octagonal prism.

To find a solid with a base that is an octagon, we can think of three-dimensional shapes called prisms. A prism is a solid that has two congruent bases and the bases are connected by straight lines on the sides. In this case, the prism with an octagonal base is called an "octagonal prism."

The octagonal prism has a base that is an octagon (a polygon with eight sides). The other face of the prism is also an octagon, and the sides of the prism are rectangular.

So, the answer to your question is the "octagonal prism."