Noun
Literally, a customs union; specifically, applied to the several customs unions successively formed under the leadership of Prussia among certain German states for establishing liberty of commerce among themselves and common tariff on imports, exports, and transit.
Source: Webster's dictionaryRecognizing this, the grand duke integrated it into the German Zollverein in 1842. Source: Internet
The entry of Saxony into the Zollverein in 1833 let trade, industry and traffic blossom farther. Source: Internet