What is a apostrophe of possession?

Answer:
Apostrophes are those little curved marks you see hanging from certain letters. They look harmless enough, so why do even well educated people throw them where they don't belong and leave them out where they're needed? Until apostrophes disappear from English altogether, you can take one step toward apostrophe reform by perfecting the art of showing possession.
Most other languages are smarter than English. To show possession in French, for example, you say
the pen of my aunt
the letters of the lovers
the fine wines of that corner bar
and so on. You can say the same thing in English too, but English has added another option, the apostrophe. Take a look at these same phrases - with the same meaning - using apostrophes:
my aunt's pen
the lovers' letters
that corner bar's fine wines
All of these phrases include nouns that express ownership. Think of the apostrophe as a little hand, holding on to an s to indicate ownership or possession. In these examples, you notice that the apostrophe is used to show that a singular noun owns something (aunt's, pen; bar's fine wines). You also see a phrase where the apostrophe indicates that plural nouns own something (lovers' letters).  

Ownership for singles

Here's the bottom line: To show possession by one owner, add an apostrophe and the letter s to the owner:
the dragon's burnt tooth (the burnt tooth belongs to the dragon)
Lulu's pierced tooth (the pierced tooth belongs to Lulu)
Another way to think about this rule is to see whether the word of expresses what you're trying to say. With the of method, you note
the sharp tooth of the crocodile = the crocodile's sharp tooth
the peanut-stained tooth of the elephant = the elephant's peanut-stained tooth
and so on.
Sometimes, no clear owner seems present in the phrase. Such a situation arises mostly when you're talking about time. If you can insert of into the sentence, you may need an apostrophe. To give you an idea of how to run the "of test," here are some phrases that express time:
one week's tooth cleaning = one week of tooth cleaning
a year's dental care = one year of dental care
When you're talking about time, give your sentence the "of test." If it passes, insert an apostrophe.
First answer by Needhelpnow101. Last edit by Needhelpnow101. Contributor trust: 0 [recommend contributor recommended]. Question popularity: 2 [recommend question].