American paper measurement of bulk formed by dividing the thickness of a sheet (in inches) by its basis weight, or the inches of thickness per pound of basis weight.

• 厚度指数:美国量度纸张厚度的一个方法。是纸的厚度（寸）除以纸的基重（磅），亦即是每磅纸的厚度（寸）。