also referred to as aoa, a of a, or alpha.
This is the angle at which the wing is presented to the airflow, in order to create lift.
0 alpha = 0 lift
too much alpha also = 0 lift!
The forward speed is also important - more speed = less alpha to achieve the same amount of lift.
if you are calm and collected when all about you are going berserk - you've missed something important!