What is the meaning of smoothing?

Also called yield curve' smoothing'. The name for a set of alternative techniques for creating continuous yield curves by connecting the dots between observed. If, for example, we have observed rates for 1, 2, 3, 5 and 10 year maturities, smoothing is the technique used to infer rates for all maturities between those known points. The known points are called "knot points". The simplest smoothing technique is "linear smoothing". The most commonly used technique is "cubic splines". For forward rates, the most accurate method is called "maximum forward rate smoothing".