"Muni" is a common abbreviation for "municipal", and sometimes becomes a frequently-used name for a city-related service or organization:

A muni is a mountain unicycle.


A muni is a sage or monastic from a religion such as Buddhism, Jainism or Hinduism.


Paul Muni (1897-1967) was an American actor.


Masaryk University Brno is often abbreviated to "Muni".


Rio Muni was a Spanish colony that is now part of Equatorial Guinea.