"What Do U Mean?" is a song by Justin Bieber from his second studio album, "Purpose". The song was written by Bieber, along with Skrillex, BloodPop, and others. It was released on August 28, 2015, and debuted at number one on the US Billboard Hot 100 chart. The song's lyrics revolve around Bieber's frustration and confusion in a relationship, with the title phrase "What do u mean?" becoming a catchy and memorable hook.

"What Do U Mean?" remains one of Justin Bieber's most popular and enduring songs. The song's catchy hook and memorable music video have made it a fan favorite, and it continues to be a staple of his live performances. The song's success paved the way for Bieber's future hits, including "Sorry", "Love Yourself", and "Intentions". As Bieber continues to evolve as an artist, "What Do U Mean?" remains an important milestone in his career, showcasing his ability to adapt and experiment with new sounds.