It took some finding, but I'm sure you really wanted to know:
DEFINITION - KNOCK ON
A knock on occurs when a player loses possession of the ball and it goes forward, or when a player hits the ball forward with the hand or arm, or when the ball hits the hand or arm and goes forward, and the ball touches the ground or another player before the original player can
catch it.
�Forward� means towards the opposing team�s dead ball line.