( ( wavelength ( ( The distance ) ( between ( ( ( adjacent peaks ) ( -LRB- ( or ( ( adjacent troughs ) -RRB- ) ) ) ) ( on ( a wave ) ) ) ) ) ) . )
(ROOT (S (VP (VB wavelength) (NP (NP (DT The) (NN distance)) (PP (IN between) (NP (NP (NP (JJ adjacent) (NNS peaks)) (PRN (-LRB- -LRB-) (CC or) (ADJP (JJ adjacent) (JJ troughs)) (-RRB- -RRB-))) (PP (IN on) (NP (DT a) (NN wave))))))) (. .)))
wavelength The distance between adjacent peaks (or adjacent troughs) on a wave .
(ROOT (S (NP (NNP Wavelength)) (VP (VBZ is) (NP (NP (DT the) (NN distance)) (PP (IN between) (NP (NP (CD two) (JJ corresponding) (NNS points)) (PP (IN of) (NP (NP (JJ adjacent) (NNS waves)) (VP (VBN called)))))))) (. .)))
Wavelength is the distance between two corresponding points of adjacent waves called.