This will be short because I want to generate discussion.
I consider torque to be a somewhat difficult topic for students. One
of the most frequently asked questions from first year students that
I answered in my office was "What is torque?" My first sentence in
answer was always "Grab the end of this meter stick and hold it
tightly." I then twisted the meter stick. "That's torque", I would
then say. Torque is twisting force, sort of. Then, of course, I got
more formal. In first year we lie to students about torque. We almost
never speak about torques as being referred to a point; we always
speak of a torque with respect to an axis. We should always be
prepared to recognize this when we teach mechanics again to the
continuing students. A "torque with respect to an axis" is merely the
component parallel to that axis of a torque with respect to a point
on that axis.
I always asked first year students to write the symbol for torque
with a subscript representing the axis to remind them that torques
must usually be referred to some point or axis. It is a small point,
but I think it helped straighten thinking about torques. Some
teachers think that subscripts should be avoided in elementary
courses. I think subscripts serve a useful purpose in many cases.