Moment of inertia tensor [1], and principal axes of rotation [2].
Principle axes are the axes where a weightless body can rotate around without "wobbling". These axes are orthogonal to each other. If a rigid body has I_1 < I_2 < I_3 moments of inertia, then rotation around the first and third axes is stable and rotation around the second axes is unstable.
Principle axes are the axes where a weightless body can rotate around without "wobbling". These axes are orthogonal to each other. If a rigid body has I_1 < I_2 < I_3 moments of inertia, then rotation around the first and third axes is stable and rotation around the second axes is unstable.
[1] https://en.wikipedia.org/wiki/Moment_of_inertia#Inertia_tens...
[2] https://en.wikipedia.org/wiki/Moment_of_inertia#Principal_ax...