Dictionary.net

The determination in magnitude and direction of the single force equivalent to two or more given forces is the C. of those forces; the single force thus found is their resultant; and they are the components of the resultant. The terms Composition, Component, and Resultant are similarly applied to velocities. When two or more ratios are expressed numerically, the ratio which the product of their antecedents bears to the product of their consequents is said to be the ratio which is compounded of those ratios. When four magnitudes are proportional, it may be inferred that the first and second together are to the second as the third and fourth together are to the fourth; this inference is said to be drawn by composition or simply componendo.