Apostrophes are one of the trickiest types of punctuation to master, apart from commas. The rules are straight forward, but the exceptions are what make them tricky. Their primary function is to indicate ownership. However, they are also used to show omission of letters, and, in very rare cases, in forming plurals. The hardest thing to master is their use with irregular nouns and compound nouns, so pay particular attention to placement when dealing with those.
Possession
The Basics
The most basic types of possession, singular and plural, are shown using either ’s or just an apostrophe.
Singular: the dog’s bone Plural: the kids’ toys
Sometimes the plural part can be tricky when you’re dealing with collective nouns or irregular plurals.
Examples: the children’s coats; the women’s restroom; the group’s assignment
But the basic idea is the same. An s is always used, and the apostrophe is placed after the s if the item’s plural already has one and before it in the case of singular possession and collective/irregular nouns.
When it comes to possession in particular, the exceptions and deviations abound. The first example of this is it’s vs. its. In this particular case, the apostrophe is indicating an omission of letters (i.e. a contraction) rather than possession, so the its without the apostrophe becomes the possessive one. It also happens to fall under a category called personal pronoun possessions, none of which use an apostrophe since they inherently show ownership. The same is true for the relative pronoun who—which changes to whose—and noun plurals (with the exception of lowercase letters, which I’ll touch more on later).
For common and proper nouns already ending in s, there is actually quite a bit of dispute. Some say you should always add ’s, and others say you should stick to just the apostrophe. Others yet say to choose depending on how the word sounds when spoken. A nice middle ground—one that is widely accepted and practiced—is to use an apostrophe without the s for proper nouns (like names) and ’s for common nouns.
Example: the mistress’s gown; the Jones’ contribution
That method is my personal preference simply because it’s a better fit than solely using one or the other, and it’s more consistent than just picking one based on how the word sounds.
Note: For names in particular, make sure you’re not changing the spelling of the last name simply because of how the possessive form sounds when you say it. This is especially true for possessive plurals of proper names ending in s, such as Jones and Edwards.
If you’re attending a party hosted by Josh and Patricia Smith, for example, it would be the Smiths’ party. But if Mr. and Mrs. Edwards have a party, an –es must be added to make the name plural BEFORE possession is indicated. It would then become the Edwardses’ party. No matter how awkward the results, names already ending in s must take on the –es ending to become plural possessives.
Tip: With plural possessives, always form the plural first, then add the appropriate punctuation for possession.
Compound Nouns and Compound Possession
For singular compound nouns (mother-in-law), the standard ’s is used.
Example: his mother-in-law's house
If a plural compound noun is used, the plural of the root noun is formed (brothers-in-law), and then the ’s is added.
Example: my brothers-in-law's cars
If the same item is possessed by more than one person, the ’s is used after the second name only.
Example: George and Cassandra’s house
If a pronoun is used in place of one of the names but there is still joint ownership, use the possessive form for both.
Correct: George’s and my house Incorrect: George and my house (possession should be shown for George) Incorrect: George’s and my’s house (my is a personal pronoun possession and already shows ownership without an apostrophe)
Correct: Her and George’s house is up for sale. Incorrect: She and George’s house is up for sale. (Even though it may sound more correct to use she, the pronoun is actually showing ownership here and is not the subject of the sentence—house is—so the possessive form her must be used.)
To show separate possession of a similar item, use the possessive form for both subjects.
Example A: Mike’s and Katrina’s cars are both blue. (They each have their own car, and both cars are blue.) Example B: The cat’s and dog’s beds are in the living room. (The cat and dog each have their own bed, and the beds are located in the living room.)
Joint ownership of more than one item is expressed the same way as a single item being possessed by those people.
Example A: Daphne and Justin’s homes are both lovely. (They jointly own more than one home.) Example B: Daphne and Justin’s dog and cat love playing outdoors. (The dog and cat belong to both Daphne and Justin.)
Amounts of time or money can be used as possessive adjectives. They are always used in the plural possessive form, requiring an apostrophe after the possessive noun.
Example A: In three days’ time, I have written ten short stories. Example B: If you want my two cents’ worth, I’d look for another house.
Note: Be aware of nouns ending in y. Changing the y to –ies does not result in a possessive, only a plural. This is a frequent mistake I run into when editing documents, particularly for businesses.
Correct: the company’s website Correct: both companies’ websites Incorrect: the companies website
Contractions and Plurals
Using Apostrophes to Omit Letters
Contractions are becoming quite common in our everyday language, and as such, most people are familiar with their use and that of the apostrophe to omit letters in word. For example, the words can’t, won’t, and aren’t are common contractions that combine the verbs can, will, and are with the word not. Most people have no problem using an apostrophe in those instances. However, when a word or number is contracted, it can be easy to accidentally use the incorrect punctuation for an apostrophe. This is mainly a problem because of the “smart quotes” feature on word processors.
Particularly in the case of fonts that use curly quotation marks for single quotes, pressing the quotation mark key to show omission of letters may result in an opening single quotation mark (‘) rather than an apostrophe (’). The key is in the curl. The curl should be in the direction of the missing letters. In other words, the tail should point down, not up.
Correct: I love rock ’n’ roll. Incorrect: I love rock ‘n’ roll.
Correct: I was born in ’64. Incorrect: I was born in ‘64.
Another thing to be careful of is the word until. Many people use 'til as the contracted form of it, but that is actually nonstandard and considered incorrect. The correct word is till, from which until was derived. Till originated around the 12th century or earlier; until didn’t pop into existence until the 13th century.
Using Apostrophes to Form Plurals
The only time an apostrophe is permitted in creating plurals is with lowercase letters. Example: Mind your p’s and q’s.
However, many grammaticians and editors don’t even use apostrophes for that purpose. So if in doubt, just don’t use them!
Any other use of an apostrophe to make a plural apart from the exception mentioned above is incorrect and deemed an “idiot’s apostrophe.” This includes writing the plurals for decades, abbreviations, and uppercase letters. While the prior practice was to add an apostrophe in these cases, it is no longer accepted as correct to do so. The only one that you could probably get away with—though the preference is still no apostrophe—is the uppercase letters.
Correct: Flared pants were popular in the 1970s and then again in the early 2000s. Incorrect: Flared pants were popular in the 1970’s and then again in the early 2000’s. Correct: Flared pants were popular in the ’70s and then again in the early 2000s. Incorrect: Flared pants were popular in the 70s and then again in the early 2000s. (An apostrophe is needed before 70s to indicate the omission of the numbers preceding it.)
Correct: How many DVDs do you own? Incorrect: How many DVD’s do you own?
Correct: I had three As and two Bs this semester! Incorrect: I had three A’s and two B’s this semester!
You should also be aware of false possessives. They often end in s but don’t indicate possession; they are simply noun-derived adjectives or adjective phrases modifying another noun.
Correct: What is your favorite Beatles song? Incorrect: What is your favorite Beatles' song?
Correct: I am not fond of New Orleans food. Incorrect: I am not fond of New Orleans’ food.
Correct: The city streets were paved with gold. Incorrect: The city’s streets were paved with gold. (This one is really tricky, but technically, inanimate objects such as a city cannot own anything; therefore, it would be incorrect to give it a possessive form.)
Also, never use an apostrophe to make a name plural. Apostrophes are only used with names to indicate possession.
Well, that wraps up The Grammar Grind series! I wanted to give special thanks to all my followers for your support on this series in particular. I’ve had a number of people come to me and say how helpful this series has been, and it’s very inspiring to know that others are finding the information useful. So thank you! I’ve really enjoyed writing this series, and I actually have a big announcement regarding this series coming up in the near future, so keep an eye out for it!