The same as the number six, but used by people who think "six" is way too long.
I entered the "No usage of words thought to be way too long when actually short" club and there were half a dozen guys armed with bats looking at me.
by Ekker October 14, 2014
BMW 6-Series
BMW 645i, 650i, and M6
"We doing donuts in them half a dozens"
by Justincredible January 7, 2013
A Half Metric Dozen is defined as either 5 or 6 depending on the situation.

To Circle logic yourself into a hole.
A- I want a cigarette.
B- You just had one.
A- No I didn’t, I had half a cigarette before, put it out then had the second half just now.
B- So you just had a cigarette.
A- No I just had half a cigarette, and another half before… wait a second… I just metric dozened myself there didn’t I?
by Myke April 15, 2004
It means that 6 of something is exactly the same as half a dozen of another. An analogy used to say what your doing isn't different then something else. Also used for objects or many other things that are similar or the same.
Sally: Its half past two.
Joe: Don't you mean 2:30
Sally: Six of one half a dozen of another.
by Actressgurl11 October 3, 2009
a term used by psychedelic chemist alexander shulgin to describe the six actively psychedelic phenethylamines he felt had the most profound and significant effects. these include "2C-B", "2C-T-7", "2C-T-2", "Mescaline", and "DOM" ("STP"). many people think that "MDMA" and "MDA" are part of this group, but nah dude.
i gotta find me some STP, im one short of sampling the magical half dozen.
by wegopijseoi December 27, 2007
When you put 6 eggs in a vagina and you put your penis and crack all the eggs so your penis comes out yellow
I saw your girl in the club so I took her home and gave her a nice dirty half dozen
by 12347385747391hohn May 15, 2014
A shortened form of "six in one-half dozen in the other".

Used to represent or describe the same outcome of two circumstances.
You could take the highway, or take city roads. It doesn't really matter, they both take 10 minutes, it's six in one-half dozen.
by Blackout_ July 1, 2019