Mechanic's Grip (poker)
A way of holding the cards popular with mechanics, because it's
easiest to deal seconds, bottoms, or middles when holding the
deck this way. A right-handed dealer holds the deck in his left
hand, with the thumb along the left edge, the forefinger at
the front, and the other three fingers curled around the right
edge.
(A left-handed dealer does the same, mutatis mutandis, with
his right hand.)
Since many no cheating players also hold the deck this way,
the grip alone is not evidence enough to accuse a player of
cheating.