1. (symbol: df) the number of elements that are allowed to vary in a statistical calculation, or the number of scores minus the number of mathematical restrictions. If the mean of a set of scores is fixed, then the number of degrees of freedom is one less than the number of scores. For example, if four individuals have a mean IQ of 100, then there are three degrees of freedom, because knowing three of the IQs determines the fourth IQ.

2. in motor control, the various joints that can move or the various muscles that can contract to produce a movement.