Particularly useful piece of English punctuation for making yourself look stupid. You can do this in three main ways:
1. Putting an apostrophe in when it's completely unnecessary.
2. Leaving it out when it's needed.
3. Putting it in the wrong place.
1. My parent's have taken control of my life.
2. Mat was Daisys hero, til he started ignoring her.
3. I do'nt know how to use an apostrophe.
by NH3 November 18, 2007
The highly unlikely, yet considerably dangerous state in which both the apocalypse, and a catastrophe, are simultaniously occuring.
Nigel: "oh shit... it's a zombie apocalypse, and a nuclear catastrophe! It's a nuclear zombie apostrophe!"
by nj412 December 12, 2010
the epidemic tendency to insert apostrophes where they do not belong
Eric has a bad case of apostrophitis- he keeps writing things like, "GREAT DEAL'S ON EVERYTHING" and "Available in 12 color's" and "He gave it back to it's owner".
by bethidee April 13, 2008
A punctuation mark often erroneously used to indicate "Beware of oncoming S!" as in "Apple's 3 for $2."
Mo Viele speculates on the origin of apostrophe abuse at her blog "fontidious":

the apostrophic epidemic

I often wonder who patient zero was.

I imagine that some lowly shopkeeper went out to paint “Bananas $3” on his sign, and was stricken with an uncontrollable urge to add an apostrophe. And soon his banana was the proud owner of $3. Not to be outdone, his rival down the street advertised “Banana’s 2 Dollar’s.” Then someone from the town full of affluent bananas went on a trip, carrying the contagion with him. “Train’s Departing Every 5 Minute’s.”

The pandemic had begun.
by Grinning Cat April 6, 2015
Not a piece of urban slang at all, but an important punctuation mark in written English, which I pride myself on knowing how to use correctly.
However, in my definition for Stoke-on-Trent, I have noticed that I made an error and put one in where it didn't belong (story of my life...).
Therefore, I'm putting this in to make myself feel better.
Wow, what a waste of your time if you read all that! Sorry!
It's only correct to put an apostrophe in "it's" if it's "it is", if not, it's "its".
by Stooo March 21, 2003
The most overused and underappreciated punctuation mark utilized in the writing of the English language. It is used to indicate the omission of a letter (elision) or letters in a word, to connect words pronounced successively (contraction), or to indicate possession.
Alternatively, and much less contemporary, is the use of the term "apostrophe" to indicate a short address by a character in a play or poem to an absent party or an inanimate object. The apostrophe in this sense allows the audience a look into the speaker's thoughts toward a person or object that cannot respond (similar to a soliloquy).
-contraction-
Correct: It's movie night.
Incorrect: Its movie night.

Incorrect: Of it's own free will.
Correct: Of its own free will.

He's not the type to say "Don't do it."

-elision-
Ned is a ne'er-do-well.

"O'er the fruited plain..."

-possession-
That is Jack's grammar book.
Jesus' life lasted 33 years.

-in a literary sense...-
Rhodora! if the sages ask thee why
This charm is wasted on the earth and sky,
Tell them, dear, that if eyes were made for seeing,
Then Beauty is its own excuse for being:
Why thou wert there, O rival of the rose!
I never thought to ask, I never knew:
But, in my simple ignorance, suppose
The self-same Power that brought me there brought you.
by Emerson (1839)
by Brain November 23, 2004
A bar shot created at random that turned out shockingly well. It consists of one part orange flavored rum, one part goldschlager and one part Southern Comfort.
The Apostrophe is the best shot in the land.
by Lepidus July 6, 2007