Definition: A 180 is when the skateboarder turns the skateboard quickly 180 degrees while in the air, so that when the skater lands the nose is where the tail was, etc.
180 degrees is the increment by which all skateboarding spin tricks are measured, first the 180, then 360, then 520, etc.
When done on the ground, this is called a "revert" and sometimes a "kickturn", though that's technically different. If the board spins 180 degrees but the skater doesn't, that would be a "shuvit". If the trick is done in the air and the skateboarder turns but the board does not, this is called a "varial".
180s are usually done along with other skateboard tricks, combining them all into one complex trick. When referring to these, the "180" part of the trick name goes first, such as a "180 tailgrab".
Pronunciation: One-Eighty
Examples:
"Jack did a 180 off the picnic table."
