To be the featured performer or main attraction at an event, or to be the main story in a newspaper.
From 'headline,' which originally referred to the heading of a newspaper article (from 'head' + 'line'). The verb sense developed in the early 20th century when 'headliner' became the top performer on a vaudeville bill.
The term came from old theatrical posters where the most famous performer's name appeared at the top in the biggest letters—and now we use it for everything from rock concerts to news stories, showing how entertainment language shapes how we talk about importance!
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