municipality vs urbs

municipality

noun
  • The governing body of such a district. 

  • A district with a government that typically encloses no other governed districts; a borough, city, or incorporated town or village. 

  • In Mexico and other Spanish- and Portuguese-speaking countries, second-level administrative divisions that may house one or more cities or towns whose head of government may be called mayors or, in Mexico, municipal presidents. 

urbs

noun
  • A walled city in Ancient Rome. 

How often have the words municipality and urbs occurred in a corpus of books? (source: Google Ngram Viewer )