( Meniscus ( ( Lens ( ( A lens ) ( which ( has ( ( ( one ( side convex ) ) , ) ( the ( other concave ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (NNS Meniscus)) (VP (VBZ Lens) (NP (NP (DT A) (NN lens)) (SBAR (WHNP (WDT which)) (S (VP (VBZ has) (NP (NP (CD one) (NN side) (NN convex)) (, ,) (NP (DT the) (JJ other) (NN concave)))))))) (. .)))
Meniscus Lens A lens which has one side convex, the other concave.
(ROOT (S (NP (DT A) (JJ concave) (NN lens)) (VP (VBZ is) (NP (NP (JJR thicker)) (PP (IN at) (NP (DT the) (NNS edges)))) (SBAR (IN than) (S (NP (PRP it)) (VP (VBZ is) (PP (IN in) (NP (DT the) (NN middle))))))) (. .)))
A concave lens is thicker at the edges than it is in the middle.