con·ca·vo-con·vex /kɑnˈkevokɑnˈvɛks; ˈkɑn, kənˈ/
  (a.)凹凸的,一面凹一面凸
  concavo-convex 形容詞
  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