A time in the 1900s the 1990s was a fun jazzy time but was less 70s and more 21st century.
Guy 1:What is that guy wearing
Guy 2:Its so nineties
by matt tomson March 20, 2014
English word in use in Ireland with the meaning of

(1) Completely wonderful, great, fantastic, etc. or
(2) Lost the head.
(1) The craic was ninety at PJ's party last night! (See craic)
(2) When he realised he'd missed the 'plane he did ninety.
by SWYman June 15, 2011
A rule for tracking computer programming development time.

The full statement of the rule is, "The first 90% of the code accounts for the first 90% of the development time. The remaining 10% of the code accounts for the other 90% of the development time."

The rule simultaneously emphasizes two important points in software development. The first is that for almost any product, most of the development time will be used on relatively small but difficult sections of the code. The second is that the first point often leads to extremely optimistic project schedules.

The ultimate lesson to learn from this rule is that the amount of the project that is completed is NOT tied to the amount of code completed, and that substituting one for the other can be disastrous.

The ninety-ninety rule is often mistaken for a typo, with users assuming that the first 90% of code should correspond to the first 10% of time; while this is logically correct, it is NOT the original aphorism.
A: "This stupid ten-line function is somehow crashing on one out of every 100 calls and nobody has a clue how to fix it. We've got a week left in the schedule and haven't even fully identified the problem."

B: "Ninety-Ninety Rule. You should have expected from the start that something like this would come up."
by DubbaEwwTeeEff November 3, 2009
Typically used in schools. When a teacher or supervisor's not around and the student aren't doing what they're supposed to (i.e. Using their device, fighting, etc), a student that first notices a teacher is coming to their classroom yells to the class, "NINETY!". Which is a code word meaning a teacher is coming. The students can then quickly get back to what they're supposed to do.
Jack: Yo, Ms. Kira's coming back!
*class scrambles back to do their work*
Ms. Kira: I'm back! Everyone doing what they're supposed to?
Class: Yes Ms. Kira
Ms. Kira: Good job!
by ShamaDama-Ding-Dong! March 28, 2018
A sexual position where a man and a woman lie back to back, with their heads at opposite ends of the bed. With none of their sexual organs are even remotely lined up.

It is favoured by people with strong religious beliefs.
Yo man last week at bible camp I had a hot Ninety-sixer with Rach. Had to go to confession afterwards, but Geez it was worth it.

I hope Jesus wasn't watching.
by GreeneryTheSecond August 9, 2010
A term declaring the nineties to be the first decade in which men could show their sensitive side and become sensitive new age guys. Referring to someone as a nineties man suggests that they are the type of guy who is not afraid to order quiche in a restaurant or cry at a movie. This evolved into the term metrosexual, a man with an excessive grooming routine, or who manscapes.
"Hey, I'm a nineties man." or "Remember when everyone used to say 'Hey, I'm a nineties man?'"
by jessperado March 7, 2013