adj.平凹的
plano concave 平面平一面凹的(平凹的)
His figure looks very funny in the concave mirror. 他的樣子在凹鏡里顯得非常可笑。
An indented or concave surface or area. 凹陷，洼地凹的表面或地區(qū)
Just as a double convex lens enlarges, so a double concave lens reduces. 正象雙凸透鏡可以放大那樣，雙凹透鏡也可以縮小。
A concave molding with a cross section that approximates a quarter circle. 飛檐的凹圓線腳截面近于九十度弧的凹線腳
