Is there a standard measure for coffee grind size? There is a lot of measurement involved in brewing coffee: the weight of the grinds, temperature of the water, etc. But as far as I can tell, there is no standardization on the size of the grinds. Recipes usually call for hand wavvy sizes like "set the grinder midway between drip and espresso grind" (for an Aeropress). Even an approximate standard would be more useful.

I'm curious if there is a standard unit of measure for grind size? If there is, do grinder manufacturers use or publish this information?
A quick search (surprisingly) revealed no standards for describing the grind. Neither the "International Coffee Organization" nor the "National Coffee Association USA" offer much more than: (from NCAUSA)


  The Grind
  
  If you purchase whole bean coffee, always grind your beans as close to
  the brew time as possible. A burr or mill grinder is preferable
  because all of the coffee is ground to a consistent size.  A blade
  grinder is less preferable because some coffee will be ground more
  finely than the rest. If you normally grind your coffee at home with a
  blade grinder, try having it ground at the store with a burr grinder.
  You may be surprised at the difference!


An author at "About.com" does offer an rather functional definition, though it lacks the authority to be called a standard:

Coarse - Very distinct particles of coffee. Like heavy-grained kosher salt. Downright chunky.
Medium - Gritty, like coarse sand.
Fine - Smoother to the touch, a little finer than granular sugar or table salt.
Extra fine - Finer than sugar, but not quite powdered. Grains should still be discernable to the touch.
Turkish - Powdered, like flour. Most inexpensive (blade) grinders will be unable to grind this finely.