Brian is an Irish name of uncertain origin, most often explained as "noble" or "high", from an old Celtic root for hill or elevation. Brian Boru, the high king who united Ireland around the year 1000, made it one of the most beloved Irish names, and it was a top 10 favorite in the United States through the 1970s. Brian still ranked number 43 in 2000 but has slipped gradually since, to number 339 in 2025.