Zentner is a German unit of mass related to the Latin centum (hundred) and centeni (per hundred). Although the measure has generally fallen into disuse, it is still sometimes used to express large weights relating to hop crops. The abbreviation for Zentner is “Ztr.” Over time, Zentner has denoted various quantities, mostly defined as 100 German pounds (“Pfund” in German), which, in turn was not itself a uniform quantity. In 1833, however, members of the Zollverein (German Customs Union) agreed to standardize all units of measurements, and they set 1 German pound to be equal to 500 grams, and 1 Zentner to be 50 kilograms. But these designations applied to Germany only. Pounds in other systems remained different. One “avoirdupois pound,” for instance, which is a measure invented by London merchants in 1303 and is still the pound in use today in the United States, is 453.5924 grams; while 1 troy pound, a French measure from medieval times and now used mainly to weight precious metals, is 373.2417 grams. The Zentner, too, had a different meaning outside Germany. In Austria and Switzerland, for instance, 1 Zentner is still considered the equivalent of 100 kilograms, that is, the Austrian/Swiss Zentner is twice as heavy as a German Zentner. In Germany, there is also a Doppelzentner (double Zentner). Its abbreviation is “dz,” and it means 100 kilograms. Confusingly, therefore, one German Doppelzentner is one Swiss or Austrian Zentner.