Staying awake, usually with the aid of caffeine and cold showers, for over 24 hours. Usually a feat performed by overworked students, but also by physicians and programmers, and other individuals who refuse to sleep until having solved some mystery.
An all-nighter is NOT simply staying up until the sun rises, then sleeping.
Jennifer felt like a zombie after having pulled two all nighters in a row during midterms week. "Really, it's not that bad after the 40th hour or so," she said, "...once you get past the hallucinations and the funny twitching thing your legs do."
Instead of pulling an all nighter, it is when you sleep early (11pm sharp) and then wake up at 5 am (or before the sun rises) in order to study for shit that don't matter
Bonard: Hey Bro, instead of pulling an all nighter after PK...I might pull a reverse all nighter
Tarun: What is that?
Bonard: It's when you sleep at 11pm sharp and then wake up at 5 am (or before the sun rises) to study for this stuff that I'm gonna forget 5 minutes after the exam is done