Not the definition of the "girth" of the barrel, but rather it's bore - the width of the hole that goes through the barrel. Also, not coincidentally, the diameter of the bullet - 9mm.
Refers to a pistol, usually a semi-automatic, ostensibly a 9mm.
Aside: The U.S. Army's standard pistol is a 9mm semi-automatic.
Universally recognised as the best number in the world, used to express something or someone's brilliance, but can also be used to describe a complete twat
When you have to pee in a movie but don’t want to miss anything, and must do the following mental equation: will the amount I have to pee cause enough discomfort to diminish my attention capacity for the remainder of the movie to an extent which is greater than the amount of the movie I would miss by making a mad dash to the restroom.
I saw Satantango last night, wonderful film but by the 5th hour I had to start doing pee calculus.
Short-hand for the word floccinaucinihilipilification, meaning the estimation of something as valueless (encountered mainly as an example of one of the longest words in the English language).