It is the minimum number of possibilities of the motion of the molecules. It value depends on the atomicity of the molecules.
A degree of freedom of a physical system is an independent parameter that is necessary to characterize the state of a physical system. In general, a degree of freedom may be any useful property that is not dependent on other variables.
The number of degrees of freedom of a dynamical system is defined as the total number of co-ordinates or independent variables required to describe the position and configuration of the system.Degrees of Freedom can be defined as independent displacements or rotations that specify the orientation of a body or system.
The degree of freedom refer to the maximum possible independent motion of the gas molecules. [Independent motion refer to translational,rotational,as well as vibrational motion.