Ono: An Ono is a bar skill consisting of a front giant done in an L-grip with a full-twisting pirouette done on one arm on bars with the initiation of 1/1 pirouette done before the handstand phase. It may be done in any style, but is now often done with the opposite arm down by the gymnast’s side for flair and style. The skill is FIG# 3.510 and is currently ranked as an E level difficulty skill.
Nastia Liukin performs an Ono pirouette, Ono pirouette plus an Ono pirouette with an additional half turn (about 25 seconds into the video).
Ono Pirouette Drill on TumbleTrak Bar
Alternate Definition of an Ono: What a gymnast says, when they lose their grip on bars.