Riflings

noun

1. The act or process of making the grooves in a rifled cannon or gun barrel.
2. The system of grooves in a rifled gun barrel or cannon. Shunt rifling, rifling for cannon, in which one side of the groove is made deeper than the other, to facilitate loading with shot having projections which enter by the deeper part of the grooves.
3. The act or process of letting playing cards cascade down one at a time towards the table (or one's hand), controlling the speed and flow with one's thumb, which sits on the top edges of the cards.