convex

convex
/ˈkɔnveks; `kɑnvɛks/ adj
with a curved surface like the outside of a ball 凸圆的; 凸面的
    a convex lens, mirror, etc 凸透镜; 凸面镜等. =>illus at concave 见concave之插图. Cf 参看 concave.

牛津英汉双解词典