Difference between torsion, out of plane, coplanar and perpendicular bends?
A molecule with N atoms has 3N degrees of freedom

3 translational modes

if it is linear, it will have 2 rotational modes; if non-linear 3

These leaves 3N-6 (3N-5 if linear) vibrational modes.  Vibrational modes are further subdivided into stretching, bending or torsional motions. 


Stretching motions can be symmetric or asymmetric
Bending motions are often referred to as scissoring, twisting, wagging, and rocking
Torsional motions refer to rotations about bonds


This diagram illustrates these various stretching and bending vibrations



Depending on the geometric relationship between the transition moment for a specific vibrational mode and the symmetry axis for the mode, vibrational modes may be further classified as parallel or perpendicular.

Here is a link to a 31 page article (slide show) that has a lot of background and pictures on this subject. Section 4.11 (page 19) might be particularly interesting to you.

One final example that you might be interested in, formaldehyde has 4 atoms and is non-linear so it will have 6 vibrational modes.  These are all pictured on page 2 in this link.