What is the name for a deliberate interruption of a journey agreed upon in advance with the airline?

A deliberate interruption of a journey that is prearranged with the airline is referred to as a stopover. A stopover typically allows passengers to leave the airport during their break in travel and to stay for an extended period, which can be beneficial for tourism or rest purposes. The airline is aware of this interruption, and the itinerary is designed to accommodate it.

In contrast, a layover usually refers to a shorter period between connecting flights where passengers remain in the airport without the option of exiting and exploring the city. A flight break is not a standard term used in aviation and connection specifically relates to a scheduled change from one flight to another without necessarily allowing for an extended break in travel.