Read Edit View history 凸凸 tūtū biconvex Origin Definitions Defs Strokes Stroke Words Sentences Sents created sense approved 凸凸 · tūtū · biconvex 2026/03/04 凸凸 tūtū biconvex convex on both sides, especially relating to an optical lens 这是一个凸凸透镜。 descriptive created sense Mar 4, 2026, 02:25 AM