If one were to stack thick fabric on top of one another, then push the opposite ends towards one another, resulting and bending and rumpling, this would illustrate what physical process?

Folding

Explanation:

A fold surface seen parallel to its shortening can be divided mainly into

hinge and limb portions, the limbs are the flanks of the fold and the hinge zone is where the flanks join together. In this last portion lies the hinge point which is the point of minimum radius of curvature (maximum curvature) for a fold. The description parallel to shortening direction is completed by the crest of the fold which represents the highest point of the fold surface whereas the trough is the lowest point. The inflection point of a fold is the point on a limb at which the concavity reverses; on regular folds, this is the midpoint of the limb