How To Make Words That End In “S” Possessive

Second only to the use of the Oxford comma, the creation of possessives for words ending in S and the S sound is one of the most hotly debated grammar topics in the English language.

The issue isn’t as cut and dried as some grammar rules, such as what punctuation is used to end a declarative sentence. (A period. Why can’t all grammar rules be this simple?) Instead, when it comes to possessives, we have a motley mix of differing guidelines issued by stylebooks, grammarians, and grade school teachers. 

There’s a word for the S sound that trips so many up: sibilant. It stems from the Latin word meaning “hissing.” It can also be used to describe other letters when they make that same S sound, such as ch, sh, z, and zh. These sibilant sounds throw people for a loop when they come at the end of a word, with many doing linguistic gymnastics trying to avoid the awkward possessive.  

Looking back in history doesn’t help settle the matter either, as the correct use of the apostrophe has always been ambiguous. The word apostrophe first appeared around 1580–90, stemming from the Greek word apostroph?, meaning “a turning away,” which makes sense as it was first used in English to represent missing letters in a word. Once it started to be used to show ownership, however, there was never any consensus as to how it should be done properly, and we live with that legacy today. 

So let’s take a look at some of the various approaches people take when addressing this possessive.

Singular nouns ending in S

Rule 1: In general, you form a possessive singular noun (both proper and common) by adding an apostrophe and the letter S to the end of the word.

  • the flower’s petals
  • Riley’s car

That’s simple enough. It’s when the car belongs to a person named Chris, or we’re talking about the petals of a crocus that the rules get blurry. Most experts and guides say you should add an apostrophe and an S to both proper and common nouns to make them possessive even when they end in S. So, using the examples above, it would be:

  •  Chris’s car
  • the crocus’s petals 

Not everyone agrees with this method, however, and some, such as the Associated Press Stylebook, nod in favor of adding only an apostrophe to make a proper noun possessive, such as:

  • Chris’ car
  • Dickens’ novels

To add even more confusion, AP Style also has an exception if the word following the possessive starts with an S, stating that in those cases only the apostrophe should be added. So it would be:

  • Texas’s people
  • Texas’ streams 

In 2019, the AP raised quite the ruckus when they tweeted that they were considering adding an S after the apostrophe for singular proper nouns, as in Mavis Staples’s album or Martha Reeves’s concert. To date, no changes have been made, but as you can see, it’s an ever-evolving, highly volatile topic. 

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Plural nouns ending in S

Rule 2: Plural nouns, on the other hand, generally don’t get an extra S, just an apostrophe. Most experts suggest you form the plural form of the word first, then add the apostrophe.

For example: 

  • the Joneses’ house 
  • the classes’ rules

Most say possessive words should generally read as you would speak them. 

The one-syllable rule

When it comes to historical proper names or those found in the Bible, however, there is another rule many choose to follow.

Rule 3: According to some, those words with two or more syllables typically just get an apostrophe after the final S, while one-syllable words getting both an apostrophe and an S.

For example:

  • Jesus’ teachings
  • Zeus’s temper

Some people apply it to more recent names as well, such as Dr. Seuss’s writings or Kenny Rogers’ songs, while others believe they all should also get an additional S

Singular nouns in plural form

Rule 4: When it comes to singular nouns that are plural words, they typically just get the apostrophe.

For example, the Beatles is a singular noun, but it’s in the form of a plural word. So, it would be:

  • The Beatles’ album

For the sake of …

Rule 5: Whether a noun ends in an S or not, if it’s followed by the word sake, most say it just gets an apostrophe.

For example:

  • for goodness’ sake
  • for conscience’ sake 
  • for appearance’ sake

Others, such as the Chicago Manual of Style, say if the word before sake ends in an S, then it should just get an apostrophe. Others should get an apostrophe and an S. So, it would be:

  • for goodness’ sake
  • for conscience’s sake 
  • for appearance’s sake

Kill the apostrophe all together?

There’s also a camp that says we should make like George Bernard Shaw and do away with apostrophes all together, be it for possessives, contractions, or anywhere else they may live. He called apostrophes “uncouth bacilli” (rough translation: “awkward bacteria”), and while we’re not sure we’d go that far, this apostrophe anarchy is admittedly a bit unnerving for those who like hard and fast grammar rules.

The bottom line is this: if what you’re writing must follow a specific stylebook, follow the rules stated there. If you’re a student, follow the rules your teacher dictates. If you’re just writing to write, then choose a method and stick to it. Consistency is the best rule. And if anyone has a problem with it, distract them with a debate about the Oxford comma.

If you enjoy the unresolved debates over grammar rules, you'll also enjoy learning about words whose pronunciations we can't agree on, either!

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