noun

• An unexpected natural or man-made catastrophe of substantial extent causing significant physical damage or destruction, loss of life or sometimes permanent change to the natural environment.
• An unforeseen event causing great loss, upset or unpleasantness of whatever kind.
• A skateboard trick involving a 180-degree ollie, landing on the center of the board with the front trucks facing towards the ramp and the back trucks over the lip. The skater then leans forwards to return in the ramp.