Definitions for v sign
Random House Webster's College Dictionary
a sign of victory approval formed by raising the index and middle fingers in the shape of aV.
Origin of V sign:
a sign (for victory); making a V with the index and middle fingers
a sign of victory or peace made with the index and middle fingers, and the palm outwards
a gesture of contempt made with the palm inwards; supposedly originated by English bowmen at Agincourt