A degree of freedom is the ability of a rigid body to move in an independent (distinct) way.
Degrees of freedom (DOF) of a rigid body is the number of independent movements it has.
A rigid body is a 3D object that is solid and does not deform or change shape.
There are six degrees of freedom in 3D space:
Three refer to rotational movement around the x (roll), y (pitch), and z (yaw) axes.
Three refer to translational movement along the x (moving left or right; sway), y (moving forward or back; surge), and z (moving up or down; heave) axes.
Rotation is a change in orientation and translation is a change in position.