One of the two top corners of a goal in a sporting event such as a soccer or lacrosse game. "Upper" refers to the top, "Ninety" refers to the ninety degree corner. They are the same as the 3 and 4 holes on an ice hockey goal. The Upper Ninety is an area of the goal that is hard to hit with the ball (due to small area and proximity to goal posts) but it is typically even harder for the goalie to cover the corners, thus making an Upper Ninety shot a feat of skill.
Jack shot from too far out but hit the upper ninety and scored anyway because the goalie couldn't jump that far and that fast to block the ball.

Jill likes to practice hitting the upper nineties of the lacrosse goal so she will instinctively shoot there during a live game.
by BTBD April 8, 2010
The most exstreme source of lippage humanly possible. When one comences to take a fatty dipper and stick up at a degree of upper ninty. This upper ninety must require skill from years possibly months of practie. The ultimate lipper was once done by a red headed prodigy by the name of NICK BIRKY.
Lippers and dippers and flippers and slippers........ No Rob shut quit im doing it ....... Rob ........ Fuck you lawlor......... ok guys are you ready. Ok just one sec..... ok ...... Upper Ninety
by Nick Birky December 4, 2003
UPPER NINETY is the ultimate fatty lipper comenced only by the few the proud the BIRKY ..... yes NICK BIRKY who just might be the Biggest player around the ladies cant resist his red hair and chain smoking habits.
by NICKOLUS December 8, 2003
the most extreme, ultimate lipper and dipper possible; instructions: take a fat ass dipper and stick into your upper lipper.
Lippers and Dippers, and Slippers and Flippers......Upper Ninety
by phisharmy December 3, 2003
hahahah HEY rob upper ninty
Rob did u catch that fatty uppre ninety
by Nick Birky December 4, 2003