when someone leaves an item in your possession overnight and for the duration of you having the item you can use it as-much as you want to and are under no obligation to give it back until they remember and ask for it back.
"Cal left his weed at mine last night so i claimed overnight rule, so you want to smoke a joint now?"
by RJ1995 September 18, 2012

When you write computer code and forget that you wrote it (or can't tell between what you did & didn't write).
Bill: "Wow, I stayed up late last night coding, now I think I'm experiencing some kind of amnesia for code. Can you have a look?".
Paul: "Sure. The code looks fine to me, plus it runs. You experienced overnight evolution bro."
Paul: "Sure. The code looks fine to me, plus it runs. You experienced overnight evolution bro."
by ruboxd July 29, 2022

A guy or girl who was once cool as fuck but seemingly turned into a dick smoke over night. This usually occurs for no reason.
by MyVeinyMeat February 14, 2022

by 0fficer May 30, 2018

When a guy cums inside a girl. And it sits inside her all night. Then he sucks it out in the morning.
by L0NGDUCKD0NG March 11, 2020

Having late night sexual intercourse.
by El Mattador October 7, 2016

a woman who is a stripper but doesnt want her friends or famliy to know she is so she tells them shes an over night baby sitter
by dylanskillin December 3, 2009
