One 

The number of times it takes to post this exact definition on Urban Dictionary before it gets accepted

Social experiment: How many times do you need to post this exact definition to Urban Dictionary before it gets accepted? One!

One by America Lover 🇺🇸 December 7, 2018

One 

Can be used as 'goodbye' or 'later'.
Short for "One Love"

Joe: "see ya tomorrow"
Nikki: "one."

One by nati May 24, 2003

One 

n. The loneliest number.

The loneliest number

One by SpoonyBard September 25, 2003

One 

To close out a meeting, dialogue or some instance of communication with another/others by equating this term with "take care."

"Ayight man, I'm bout to bounce, I'll holla at you later. One."

One by Aaron August 5, 2003

One 

Regarded by many as the best Metallica songs. The song portrays a young soldier who is returning from war, suffering massive damage from a landmine. He cannot speak, he cannot move, he is essentially a head with no body.

Metallica did two versions of this song originally, the original and the rare version. In the rare version, during the long instrumental sections it is filled with speaking, the speaking of the soldier in his mind, the doctors, and his father. The boy pleads for his father to kill him, the doctor realizes the mistake of taking this patient and making him live through this "hell".

On "...and Justice for All."

One by Aaron March 5, 2005

one 

means goodbye, spoken as a true gangsta

You leavin? Aight one bro."

one by P Schizzle October 3, 2003

one 

A great answer to give in math class when a teacher asks you a question to make sure you are paying attention, and you don't know it because you really weren't paying attention.

Great because it is more likely to be the right answer than any other number. Also, even if you're wrong, everybody will think it was just a joke and you will come out on top.

Do not try in other classes or you will look like a dumbass.

Me: zzz... "snore"

Mr. Lashower: Erick, would you please tell me what anything to the power of zero is?

Me: "wakes" Uhhhh.... one?????

Mr. Lashower: Yes, that's the correct answer.

Me: Bitchin'. This shit works.

OR...

Me: zzz...

Mr. Goldfischer: Erick who won the Battle of Stalingrad?

Me: One?

Classmates: WTF ?!?!

one by Erick A. C May 24, 2009