A "running theme" refers to an idea or topic that frequently appears or is repeated throughout a story, conversation, or situation. It is an ongoing element that helps to connect different parts and provide a central focus. Full definition
Once you have found two or three, you can look for running themes in keywords and phrases. (maryelizabethbradford.com)
Their entertainment is provided by a mega corporation that runs a theme park that contains all of the hopes, dreams, and physical activities denied the average person. (waypoint.vice.com)
So like most anthology movies, what's the common running theme in all of them? (mediamikes.com)