Apostrophes

Possession

an icon showing an apostropheWith possessives, the apostrophe is used in combination with an s to represent that a word literally or conceptually possesses what follows it.

  • a student’s assignment
  • the county’s borders
  • Kamala’s decision
  • one hour’s passing

Apostrophes with Words Ending in s and with Plurals

Singular words, whether or not they end in s, are made possessive by adding an apostrophe + s. For plural words, we typically indicate possession simply by adding the apostrophe without an additional s. However, for a plural that does not end in an s (e.g., bacteria), we would add an apostrophe + s.

  • Illinois’s law
  • Mars’s atmosphere
  • interviewees’ answers
  • the bacteria’s life cycle
  • her professors’ office (an office shared by two of her professors; if it were just one professor we would write her professor’s office)
Note: Practices for handling apostrophes with words ending in s vary from style to style, sometimes using syllable count as the determining factor, for example, so you might need to check the conventions in your course’s discipline.

Contractions

A contraction is a shortened phrase. He will becomes he’ll, are not becomes aren’t, would have becomes would’ve, and it is becomes it’s. In all of these cases, the apostrophe stands in for the missing letters.

You may find yourself being steered away from using contractions in your standardized academic papers. Write to your teacher’s preference. Leaving out contractions can possibly make your writing sound too formal and stilted, but using contractions can make your writing sound too informal and casual. And don’t eliminate contractions in your papers just to up your word count!

Note: Double contractions, like wouldn’t’ve or I’d’ve are considered non-standardized and are typically avoided in formal written language.

Some Common Errors

Now that we’ve learned about both contraction and possession, let’s take a look at some of the most common (or at least most called out) errors people make.

Its versus It’s

This convention also applies to your vs. you’re and their vs. they’re. The best way to use these conventionally is to remember that possessive pronouns never have an apostrophe: if there’s an apostrophe with a pronoun, it’s a contraction, not a possessive.

Should’ve versus Should of

  • Should of, would of, could of
  • Should’ve, would’ve, could’ve

This confusion is due to the pronunciation. Out loud both of these phrases sound exactly the same. However, remember that the original phrase is should have, as in “I should have selected that.” Unfortunately, the only way to remember this is rote memorization (or perhaps a closer examination of the word of).

Acronyms and Numbers

In technical writing, acronyms and numbers are sometimes pluralized with the addition of an apostrophe + s, but this convention is falling out of favor, and there is typically no need to put an apostrophe in front of the s. Therefore, SSTs (sea surface temperatures) is more acceptable than SST’s when your intention is simply to pluralize.

Ideally, use the apostrophe before the s with an acronym or a number only to show possession (e.g., “an 1860’s law” but “in the 1860s”; “DEP’s testing”) or when confusion would otherwise result (“mind your p’s and q’s”).

When talking about a specific decade the 1920s should be shortened to the ’20s. Notice that the apostrophe curls away from the numbers, indicating that the missing characters originally appeared prior to the apostrophe.

Practice

Select the response from the list that best completes the sentence.

  1. Betty Crocker actually came from an (employees/employee’s/employees’) imagination.
  2. Back in the (1930s/1930’s/1930s’), Betty Crocker was a name everyone knew.
  3. A television commercial asked, “(Who’s/Whose) the person (who’s/whose) cookies we love?”
  4. As (woman’s/women’s/womens’) fashions changed, the company updated (Betty Crocker’s/Betty Crockers’) image.
  5. A commercial told us, “Buy Betty Crocker. (It’s/Its) quality you can trust!”