Now that we know how apostrophes ended up showing possession in the English language, it’s time to learn a handful of modern rules.
Basic Rules of the Possessive Case
- First make sure that you need to use a possessive.
Does an of phrase make sense of what you are trying to say? For instance, Fido leash does not convey much information to the reader, while the leash of Fido is at least understandable. On the other hand, chair leg makes sense as written. There is no need to write the leg of the chair. In this case, the of phrase adds strictly to the word count, not the meaning. Inanimate objects cannot possess anything—typically. For emphasis or personification, however, the so-called false possessive is perfectly acceptable: nature’s beauty; the laws of nature. Also acceptable is the use of an apostrophe to express a measure of something, as in a dollar’s worth.
To make a singular noun possessive, add -’s to the end of the word.
This rule applies regardless of the word. Just as the possessive of dog is dog’s, the possessive of Jones is Jones’s. Some writers complicate this rule with exceptions, suggesting that the sound of the word should dictate the correct punctuation. However, there are exceptions enough already. The -’s form is mandatory for formal writing and preferable for informal writing anyway; why not use it? The only exceptions that we unfortunately have not dispensed with yet are certain ancient names and phrases, such as Augustus’ likeness and for conscience’ sake. Perhaps in time writers will not have to struggle with such cases as these. For now, however, we need not encumber the rules of mechanics with still more exceptions.
- To make a plural noun ending in -s possessive, add an apostrophe to the end of the word.
If the word is dogs, the possessive is dogs’. If the word is foxes, the possessive is foxes’.
- To make a plural noun that does not end in -s possessive, add -’s to the end of the word.
If the word is women, the possessive is women’s. If the word is sheep, the possessive is sheep’s, even if we have a whole flock in mind.
- Do not use an apostrophe on possessive personal pronouns or on the relative pronoun who.
These pronouns are remnants from the days when English was an inflected language. They show possession by changing form. He’s means he is, not his; likewise, it’s means it is, not its.
- Treat indefinite pronouns as you would nouns.
Unlike personal pronouns, indefinite pronouns are not inflected. Somebody’s gloves is correct.
- Never confuse possessives and plurals.
They have two entirely different roles. Two dog’s ran is a meaningless sentence. My to-do’s are piling up is, as well. There are very few times when an apostrophe is used to form a plural. The exceptions are letters, numbers, and words referred to as words, not objects or concepts (for example, not’s in avoid using so many not’s in your writing). Dot your i’s uses an apostrophe to mark a plural. The reason is that confusion can result from a simple s: dot your is. Note, however, that the ABCs of car repair does not need an apostrophe because ABCs is not confusing and because it has been accepted as a word in its own right. Also, years do not take apostrophes because awkward scenarios can sometimes arise. For instance, suppose that we are writing about the 1930s. If we had used the form 1930’s and we chose to shorten this to ‘30’s, the result would be unattractive, to say the least.
The basics from Purdue’s Online Writing Lab (OWL) in printable form.
10 Ways to Use Notebooking: #5 Grammar & Spelling
Ideas, resources, and printables for creating grammar notebook pages on possessives.
Using Apostrophes for Possession
Interactive that teaches the basics.
Catastrophes of Apostrophic Proportions
Interactive quiz to practice using the rules above.
Interactive from Time for Kids that helps students practice possessives. Press the Try Another button in the right-hand corner for more practice.