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An apostrophe is a commonly used punctuation mark with a few specific jobs. In appearance, it looks like a single quotation mark (‘).
An apostrophe is used mainly to indicate possession and to create contractions.
In this refresher, we’ll cover when to use apostrophes in your writing and when not to.
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The apostrophe is most often used to indicate possession. In grammar, possession refers to the relationship between two things. The relationship is often one of ownership. However, it can also be one of very close association or belonging.
Examples of possession in grammar:
In the first example above, instead of the toothbrush belonging to just anyone and everyone, we know it is ‘his’ toothbrush. His is the possessive here.
Tip: An apostrophe is never used on any of the possessive pronouns (my, mine, your, yours, her, hers, his, our, ours, their, theirs).
An apostrophe is needed to form the possessive of nouns (singular, plural, proper, and compound). For instance, if the toothbrush above belongs to Frank, it is Frank’s toothbrush.
Below, we’ll cover examples of how that works and other instances where an apostrophe is used to create possessives.
To form the possessive of a singular noun, add an apostrophe and an s.
Examples of the singular possessive with an apostrophe:
An apostrophe is used without an s if the plural noun ends in s.
Examples:
When a plural noun does not end in s, add the apostrophe and an s.
Examples:
Proper nouns — nouns that name a specific person, place, or thing — can also be made possessive with the use of apostrophes.
According to most style guides (see our note on style guides in the next section), apply the basic rules of forming a possessive: add an apostrophe and an s for a singular noun, or add just an apostrophe for a plural noun.
Examples with singular proper nouns (apostrophe + s)
Examples with plural proper nouns (apostrophe only):
Depending on the editorial style followed by your organization, singular nouns ending in an s may be treated a little differently when becoming possessive.
For instance, The Chicago Manual of Style, American Psychological Association (APA), and Associated Press (AP) Stylebook all have instructions on how to treat nouns ending in s. Sometimes they align. However, there can be exceptions or preferences across the guides that differ.
Let’s take a look at an example:
In this case, AP Style recommends only using an apostrophe because Dickens is a singular proper name with ‘s’ as the last letter. However, both the Chicago Manual of Style and APA prefer if an apostrophe and s are added.
If you are ever in doubt about how to turn a noun ending in s into a possessive, consult your organization’s style guide.
A contraction is a word that is created when you shorten and merge two words into one. A contraction can also be an abbreviated number.
In contractions, an apostrophe takes the place of the omitted words, letters, or numbers.
Examples:
If your font uses a curly apostrophe (the one that looks like an upside-down comma), rather than a straight apostrophe, the curve and opening must point to the left (’) to indicate digits are missing.
Examples:
The plural of a family name does not get an apostrophe and an s, except when indicating possession:
Examples:
Remember a case like whether Thompsons’s or Smiths’ has an apostrophe and s, or just an apostrophe, could vary depending on your style guide (we’ve included examples of both above).
Common phrases or terms may be exceptions like:
Both of these examples use an apostrophe. They’re not technically possessives but are called quasi-possessives in grammar.
If two nouns share possession of something, it’s called a shared possessive, and the apostrophe only goes on the last noun.
For example, if Jim and Judy have kids together, the possessive is:
However, if two nouns possess things independently, each noun gets an apostrophe in the possessive.
For example, if Jim has two kids and Judy has two kids the proper grammar is:
Example: dot your i’s and cross your t’s. This varies according to style.
While the main jobs of apostrophes are somewhat clear, as with all grammar, there are exceptions and minutia that you may need to look up in your organization’s preferred dictionary or style guide when you run into them.
For best practice check your grammar with the Originality.ai AI Grammar Checker to catch any punctuation, grammar, or spelling mistakes.
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