Fashion just lost its queen bee -- Anna Wintour is stepping down from 'American Vogue,' ending her legendary era with a clap heard around the runways of the world.

The 75-year-old dropped the bombshell in a staff meeting Thursday -- revealing she’s on the hunt for a new head of editorial content at the fashion bible.

Anna’s reportedly not ditching the fashion world completely -- she’s still sticking around as Vogue's global editorial director and Condé Nast’s chief content officer ... overseeing heavyweight magazine titles like Vanity Fair, GQ, Architectural Digest, Glamour, and more.

The media powerhouse took the reins at Vogue in 1988 after a few years at 'British Vogue' -- and completely rewrote the rules, turning the mag (and fashion media) into the juggernaut it is today.

Anna also became a pop culture fixture herself. Known for her icy, no-nonsense vibe, she sparked endless curiosity about her life and career ... especially after "The Devil Wears Prada" film dropped, loosely based on her ex-assistant’s tell-all.