Extra moenia is a Latin phrase that means outside the walls or outside the walls of the city.
The phrase is commonly used in reference to the original attributes of a building, usually a church, where it was built outside the original city walls. Hence, when a city expands over time, a church which was originally outside the walls might end up in the center of the larger city; subsequently, to retain the original architectural context, it would be referred to as extra moenia. Two examples of this are the Basilica of Saint Paul Outside the Walls in Rome, and San Gennaro extra Moenia of Naples.
The term is also used to indicate an occurrence or activity taking place outside the venue where it would normally be used or reside.