Uses:
1. Adding an apostrophe to a noun indicates that something belongs to it. To determine whether or not an apostrophe should be added, conduct a simple test that turns the phrase around to be “of the…” subject.

• The boy’s cat or “The cat of the boy.” (correct)
• The lady’s purse, or “The purse of the lady.” correct)
• The boat’s sail or “The sail of the boat.” (incorrect)

In the third example, the boat did not have to take on the possessive form because the noun after “of the” was one of three exceptions for the “of the…” test: a building, an object, or furniture piece. Rather, it can simply be written as “the car door” to signify the door belongs to the car.

The apostrophe is placed in different parts of a word. For singular words, add an “’s” to the end, even if the final letter is an “s.”

• The king’s crown was silver.
• Jarvis’s writing is terrific.

For plural words that end in “s,” simply add an apostrophe.

• The cows’ tails swung from side to side.

When plural words do not end in “s,” add an “s”.

• The children’s rooms were untidy.

Note that for compound words and the last noun of a joint possession, an “s” is added.

• sister-in-law’s
• Jack and Jill’s

For contractions, replace missing letters with an apostrophe; but remember that it’s where the letters no longer are, which is not always where the words are joined. An example would be “is not” and “isn’t.”

• You are = You’re
• We are= We’re
• Do not = Don’t
• Should not = Shouldn’t

Misuse:
Make sure not to misplace the apostrophe because it can change the meaning of a word, such as “it’s” and “its.” Or, if it is missing from a word like “there’s,” it’s a spelling error: “theres.” This is especially confusing if the context suggests the true meaning might be “theirs.”

So pay careful attention to the apostrophe. Getting its usage right is critical to writing better emails, documents, and sales letters.