What does the triangle/diamond symbol that Jay Z, Kanye, Beyonce and Rihanna all do with their hands at their concerts mean?

The hand sign Jay-Z, Kanye West, Beyonce and Rihanna do is called the Diamond Cutter, and is used to promote Jay-Z’s Roc-A-Fella record label and clothing line.

In 2005, Jay-Z was sued by former pro wrestler Diamond Dallas Page for copyright infringement for the hand sign. Page used a similar hand sign during his wrestling career, and called his finishing move the Diamond Cutter. Page ended up dropping the lawsuit for an undisclosed about of money.