amphicyrtous: -η, -ο (Α ἀμφίκυρτος, -ον) [etymology < ἀμφι-* + κυρτός.
curved on both sides /gibbous / phase of moon or planet between first quarter and full or between full and last quarter / convex / a convex lens drives the diverging, or blurred, light rays from a distant object to converge at a focal point