ALL meanings of parallelogram law
par·al·lel·o·gram law
P p - noun parallelogram law Mathematics, Physics. a rule for adding two vectors, as forces (parallelogram of forces) by placing the point of application of one at the point of origin of the other and obtaining their sum by constructing the line connecting the two remaining end points, the sum being the diagonal of the parallelogram whose adjacent sides are the two vectors. 1