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1 definition by Uni-wan-Kenobi

In unicycling, an unplanned dismount. Not a fall per se, but something that causes you to step off or otherwise end up off of the unicycle without any injury or dramatic falling.
Unseen bumps can cause occasional UPDs, but as riding ability increases, chances are you will just have the shit scared out of you.
by Uni-wan-Kenobi July 18, 2005