The number of degrees of freedom in a problem, distribution, etc., is the number of parameters which may be independently varied.
Degree of Freedom
See also
Likelihood RatioExplore with Wolfram|Alpha
Cite this as:
Weisstein, Eric W. "Degree of Freedom." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/DegreeofFreedom.html