ONS 

ONS is an acronym indicating the common dating phenomenon One Night Stand. You can use the acronym ONS to indicate a person with whom you have had said One Night Stand.

You: "Uh-oh, guess who just walked in?"
Me: "Shit. Who?!"
You: "ONS"
Me: "Great... and I thought I'd never have to see him again."

ONS by Roberta Pincer April 11, 2005

ONS 

One Night Stand

In the past month i've had 31 ONS's

ONS by craig March 12, 2003

Ons 

One night stand

Last night I had an ons.

Ons by Queens Inspire Kings June 27, 2016

ONS 

This stands for "One-Night-Stand" and is used by some males to inform thier friends what they think of certain women in the club.

Check her out!! She is definately an ONS I wouldnt mind havin tonite!

ONS by Shinshoryuken January 14, 2006

ONS 

Onslaught, a game mode in Unreal Tournament 2004 where players trying to capture nodes to eventually make way to the enemy base and try to destroy the power core.

It takes good team strats to win at ONS.

ONS by CorporationX February 17, 2005

ons 

it means “on a set.” you use it if something is true

Messages ....
Madison : Yooo they are couple goals *sends a picture*
Jay : ons

ons by jayyyroddddd January 7, 2020

ONS 

ONS is an abbreviation for "Over Night Studying", SON can also be used in some occasions. It is an action held by most, if not all, petroleum engineering students. It has been well known through out time, that this habit is to be practiced before major exams, and even quizes. According to new Petroleum engineering students, ONS is a sacred retual, that every -successful to be- engineer should experience!

"Normal student Helal" : Ughh, Got a midterm tomorrow, ONS :D ??

2 years later..

"ADMA executive manager HaLool :3" : SON was worth it alright :3!

ONS by Hallulz November 22, 2010