( ( Distance ( between ( two points ) ) ) ( , ( ( ( expressed ( in ( wave lengths ) ) ) ( at ( a ( specified frequency ) ) ) ) . ) ) )
(ROOT (S (NP (NP (NNP Distance)) (PP (IN between) (NP (CD two) (NNS points)))) (, ,) (VP (VBD expressed) (PP (IN in) (NP (NN wave) (NNS lengths))) (PP (IN at) (NP (DT a) (VBN specified) (NN frequency)))) (. .)))
Distance between two points, expressed in wave lengths at a specified frequency.
(ROOT (S (NP (NNP Distance)) (VP (VBZ is) (NP (NP (DT the) (NN term)) (PP (IN for) (NP (NP (DT the) (NN length)) (PP (IN of) (NP (NP (DT the) (NN route)) (PP (IN between) (NP (CD two) (NNS points))))))))) (. .)))