There are various types of coffee grind depending on your brewing technique.
Coarse Grind (Cafetiere or French Press)
This type of grind leaves the largest granules of coffee and is preferred for French Presses (a.k.a. plungers) or the percolator method of brewing.
Medium Grind (Filter or Vacuum)
Medium grinds have a consistency of granulated sugar and are primarily recommended for vacuum and certain types of drip coffee makers. Because of its versatile size, it can also be used for other brewing methods, but not espresso.
Fine grind (Espresso)
Also known as an espresso grind, this is a grind with a powdery/mealy consistency used in espresso makers and Neapolitan flip-drips though electric drip and filter brews can use it as well.
Extra Fine Grind (Turkish)
Like fine flour, this extremely fine grind is the province of Turkish coffee and usually needs to be ground in a special grinder.