( ( ( A ( vector quantity ) ) ( possessing ( ( size and ) direction ) ) ) . )
(ROOT (NP (NP (DT A) (NN vector) (NN quantity)) (VP (VBG possessing) (NP (NN size) (CC and) (NN direction))) (. .)))
A vector quantity possessing size and direction.
(ROOT (S (NP (NNP Vector)) (VP (VBZ is) (NP (NP (DT a) (NN measure)) (SBAR (WHNP (WDT that)) (S (VP (VBZ has) (NP (DT both) (NN size) (CC and) (NN direction))))))) (. .)))