(eks-ten'sÅr, -sÅr), [TA] 1  A muscle the contraction of which causes movement at a joint with the consequence that the limb or body assumes a more straight line, or so that the distance between the parts proximal and distal to the joint is increased or extended; the antagonist of a flexor. See: muscle.
All other things being equal, using internal rate of return (IRR) and net present value (NPV) measurements to evaluate projects often results in the same findings. However, there are a number of projects for which using IRR is not as effective as using NPV to discount cash flows.
Most financial metrics used in business belong to one of two families: Cash Flow Metrics. These include metrics such as net present value (NPV), return on Investment (ROI), and internal rate of return (IRR), used for evaluating investments and streams of cash flow events.