半凸半凹面的
Convexo-concave \Con*vex"o-con"cave\ (?or ?), a. Convex on one side, and concave on the other. The curves of the convex and concave sides may be alike or may be different. See {Meniscus}.
convexo-concave adj : convex on one side and concave on the other with the convexity being greater than the concavity