Terminology question: could this be called an "ill conditioned" problem

I have a question regarding mathematics terminology.

In the picture below, there are two surfaces that both have the minimum (=0) at the origin. If an optimization algoprithm were to try to find the minimum of the conical surface to the left, I would think it is easy for an optimization algorithm to find this distinct minimum. While on the other hand, the "bathtub" surface to the right, have many points around the origin that are very close to the minimum, and it would thus be more difficult to find this minimum. Many combinations of x and y end up in a function value very close to the minimum. Is there a mathematical term do describe the "bathtub"-type problem in contrast to the "cone"-problem?