A segment was a portion of a program devoted to a specific genre or topic.
In 2372, Neelix assured The Doctor that Hints for Healthful Living had the potential to become a popular segment on his news program, A Briefing with Neelix. Later, after having been excluded twice on the show, The Doctor confronted Neelix, reminding him that he had been scheduled to do two segments that day after having been forgotten the first time. (VOY: "Investigations")