An Italian city or (later) one in the provinces whose citizens held the privileges of Roman citizens.
The exact constitution of a municipium and the extent of citizen rights varied from city to city, most notably in respect of the right of voting at Rome (ius suffragii)..
Origin
Early 18th century; earliest use found in Phillips's New World of Words. From classical Latin mūnicipium from mūnicip-, mūniceps + -ium.