Apostrophes | Definition, Guide, Rules & Examples
Apostrophes have two main uses:
- Indicating possession (e.g., The student’s paper)
- Indicating a contraction (e.g., She’s writing a paper)
Contractions should be avoided in academic writing, but possessive apostrophes are used in all types of writing. Make sure to use them correctly, especially when dealing with plurals and abbreviations.
|Use a possessive apostrophe…|
|This study examines the company’s efforts to expand.
I highly recommend Sharon’s salon.
|My parents’ support was essential.
The crowd’s applause could be heard for miles.
|In the last quarter, BP’s profits dropped.|
|Don’t use an apostrophe…|
|The results are surprising.
Remember what happened three Christmases ago?
|Several NGOs were present at the conference.
We can identify the following KPIs.
|The 1920s was a golden age for art.
During the 2010s politics slid into confusion.
|The cobra reared its head.
Whose snake is that?
Possessive apostrophes with singular nouns
Apostrophes are used to indicate that something belongs to something or someone else.
To indicate possession with a singular noun, add ’s at the end of the word. This also applies to names and other proper nouns.
With proper nouns that ends in s, most style guides – including APA and MLA – recommend adding ’s.
Some guides allow you to add only an apostrophe in cases where the extra s would be awkward to pronounce aloud. If in doubt, however, adding ’s is the safest choice.
Note that when you are citing a source, the apostrophe is attached to the author’s name, not to the in-text citation.
Possessive apostrophes with plural nouns
Most plural nouns already end in s. In this case, to indicate possession, add only an apostrophe to the end of the word. This also applies to words where the singular and the plural take the same form.
The same rule applies to proper nouns and singular entities that end with a plural noun.
If a plural noun does not end in s, add ’s as you would for a singular noun. This also applies to collective nouns, uncountable nouns and acronyms.
Pronouns stand in for nouns. Possessive pronouns (e.g., mine, yours, hers, his, our, their, its) indicate that something belongs to someone or something. These pronouns do not take an apostrophe.
Indefinite pronouns (e.g., someone, something, anybody) do take an apostrophe.
- This match could be anybodys game.
- This match could be anybody’s game.
When multiple nouns jointly own one noun, an apostrophe is added after the last noun only.
In these examples, the same love is possessed by both Frida and Diego, and the same paper was written collectively by McDonald, Ferriss and Bane.
When multiple nouns individually own other nouns, however, add an apostrophe after all of the owning nouns.
In these examples, the scientist and the robot possess two different sets of abilities, and the engineers and the operators face two separate kinds of problem.
Sometimes one or more letters are omitted to shorten a word or term. An apostrophe is used to indicate missing letters.
However, contractions are informal and are usually not appropriate to use in academic writing.
Apostrophes to form plurals
In English, an apostrophe should almost never be used to form a plural, including with acronyms and decades.
There are rare exceptions to this rule, such as pluralizing letters of the alphabet.
Possessive pronouns vs contractions
One of the most common apostrophe mistakes is confusing possessive pronouns with contractions that look or sound similar. Always pay attention to whether an apostrophe is intended to indicate possession or a contraction, and remember that possessive pronouns don’t take apostrophes.
It’s vs. its
It’s is a contraction of it is.
Its is a possessive pronoun indicating that something belongs to it.
They’re vs. their
They’re is a contraction of they are.
Their is a possessive pronoun indicating that something belongs to them.
Who’s vs. whose
Who’s is a contraction of who is or who has.
Whose is a possessive pronoun indicating that something belongs to them.
Sources in this article
We strongly encourage students to use sources in their work. You can cite our article (APA Style) or take a deep dive into the articles below.This Scribbr article Sources