Siuu is Cristiano Ronaldo's signature goal celebration, with siu meaning yes in Portuguese, and the shout has followed him from Real Madrid through Juventus, Manchester United and Al Nassr. Fans began copying the jump, spin and landing pose in stadiums and on social media, and the sound became a staple of football edits, TikTok videos and stadium chants. It remains popular because it is instantly recognisable, easy to imitate and tied directly to one of football's most famous scorers.