Glass Terminology
Glasses named after their shape:
Kelch cup, goblet, chalice: Has no stem like the Pokal
Krug (or Seidel): what Americans call a
mug. The only beer glass with a handle. 
An example of the Pokal is shown in the accompanying photo
Stange (stick): very similar to a pilsner except taller and more slender.
Willibecher (or becher - a cup): what Americans would call a tumbler
Glasses named for the style of beer they are intended to hold:
Alt: a cylindrical glass that usually holds only 0.2-0.3 Liters. A North German style where they drink their beer in smaller portions.
Berliner Kindl: similar to an American schooner. A "fish-bowl" on a stem.
Kölsch: similar to the Altbier glass but of thinner glass, and sometimes taller. Smaller capacity, in the Northern German style.
Pilsner (Pils): A German pilsner glass is the Pokal. An American pilsner glass is an inverted cone on a short pedestal.
Weissbier (also called weizenbier): Large, (usually 0.5 L) inverted cone without a pedestal.
It should be understood that many new styles of glasses, or hybrids, have evolved over the years and there is not always agreement over what style name should be applied to a particular glass.