( ( weight ( ( The force ) ( of ( gravity ( acting ( on ( an object ) ) ) ) ) ) ) . )
(ROOT (S (VP (VB weight) (NP (NP (DT The) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBG acting) (PP (IN on) (NP (DT an) (NN object)))))))) (. .)))
weight The force of gravity acting on an object.
(ROOT (S (NP (NNP Weight)) (VP (VBZ is) (NP (NP (DT the) (NN measure)) (PP (IN of) (NP (NP (DT the) (NN force)) (PP (IN of) (NP (NP (NN gravity)) (VP (VBG pulling) (PRT (RP down)) (PP (IN on) (NP (DT an) (NN object)))))))))) (. .)))