凹凸的,一面凹一面凸
Concavo-convex \Con*ca`vo-con"vex\, a. 1. Concave on one side and convex on the other, as an eggshell or a crescent. 2. (Optics) Specifically, having such a combination of concave and convex sides as makes the focal axis the shortest line between them. See Illust. under {Lens}.
concavo-convex adj : concave on one side and convex on the other with the concavity being greater than the convexity