Apostrophes 101


The apostrophe may be the most misunderstood punctuation mark in English. There are even websites dedicated to cataloging its misuse. Most punctuation marks fall between words to separate ideas or grammatical clauses, but the apostrophe is used within words and to combine multiple words which befuddles even native speakers.

This small mark has two primary uses: to signify either possession or omitted letters. Rather than say “the friend of Sam,” one can say “Sam’s friend” by adding a ‘s to the possessor (in this case, Sam). As for the second use, some common English words can be combined into a contraction, such as isn’t, don’t, and you’re. We often elide sounds and letters when speaking for the sake of convenience, and the apostrophe helps written language reflect its spoken equivalent. The word apostrophe comes from the Greek word apóstrophos which refers to a mark used in Greek to signify an omitted letter. It literally means a “mark of turning away.”

The apostrophe causes so much strife in part because it’s the culprit in two of the most commonly confused pairs in English: you’re/your and it’s/its. Possessive pronouns (like your and its) never take apostrophes, but their soundalike friends are contractions that require apostrophes. We all struggle with these when writing and proofreading our work, but here’s a trick: try replacing the ‘re or ‘s with are or is. If the syntax works, then you need the apostrophe; if not, it’s the possessive pronoun. For example, “It’s Sunday” can be written “It is Sunday,” while “The school locked its doors” cannot be written “The school locked it is doors.” Likewise, “You’re late” can be written “You are late,” while “I saw your note” cannot be written “I saw you are note.”

What about when you see an apostrophe at the end of the word? If there are multiple possessors, as in the teachers’ dog (which refers to a dog belonging to multiple teachers), the apostrophe is placed outside of the s. But in English there’s always an exception. For plural nouns that do not end in s, add ‘s, e.g. women’s rights. Also, the apostrophe is added for the possessive of a noun that is plural in form but singular in meaning, e.g. mathematics’ formulas. Lastly, for joint possession, the ‘s is added to the word nearest the object of possession, e.g. Francis and Kucera’s book.

The apostrophe has a number of other lesser-known uses. It can replace omitted numbers (e.g. the class of ’72, the ’20s, etc.) and letters e.g. gone fishin’. It can also be used to indicate plural letters, as in p’s and q’s, two A’s and four B’s, etc.

When you get confused, here’s a useful flowchart from The Oatmeal. Some pundits want to do away with the apostrophe altogether. Do you think that’s a good idea?

See Also:
How do you use this slippery piece of punctuation: the slash?
What character was removed from the alphabet?
What is the real name of the #?



  1. Bart -  July 19, 2014 - 1:36 pm

    The article states that “Possessive pronouns (like your and its) never take apostrophes…”. This is not correct. The exception is the pronoun “one,” the possessive of which is “one’s” not “ones.”

    • Anne Ominous -  July 20, 2014 - 11:18 am

      But it’s only an exception to the extent that “one” is itself an exception to the usual pronoun rules.

      Most possessive pronouns imply a relationship to the speaker, even if indirect: “your”, “my”, “his”, “her”, “its”.

      “One”, on the other hand, is used as the proper name of a theoretical person: “One must not,” replaces “John must not,” and “One’s property” replaces “John’s property”. Much in the same way that “whom” refers to an unknown (as opposed to present company) person.

      So the rules regarding “one” are those of proper names, not those of normal pronouns, since its purpose is that of a “generic” proper name.

  2. Brian Vanderjack -  July 19, 2014 - 10:25 am

    Surprised your editors did not flag o’clock as a poor word choice for this particular article. Was about to refer my students here, rather than Grammar Girl for this topic; then I noticed this lapse in clear thought on the part of your editors.

    • Anne Ominous -  July 20, 2014 - 11:24 am

      O’clock is a straightforward contraction of “of the clock” (according to the clock). I don’t understand why you think it’s an exception.

  3. А -  July 19, 2014 - 9:31 am


  4. Cindy -  July 18, 2014 - 8:10 am

    Question: What about using an apostrophe to show that the doors belonged to the school. All silliness aside, I might have put an apostrophe in just to make it possessive. The school locked it’s doors. Some of the rules I learned 30+ years ago are so ingrained they might as well be written in the firmament, but as I age I tend to slip up on others. It is really irritating.

  5. Lexy -  July 17, 2014 - 5:46 am

    Leave it to the pundits whom presume to know what’s best .

    • Dave -  July 19, 2014 - 7:57 pm

      …the pundits who…

      Yaw welcome :))

  6. VoidPhantom -  July 17, 2014 - 4:33 am

    In what universe is “mathematics” plural in form? You don’t say “mathematics ARE,” you say “mathematics IS.” Just because it ends with an S doesn’t mean it’s plural (consider, for example, the word “class”).

    • Anne Ominous -  July 20, 2014 - 11:33 am

      Mathematics is indeed a plural. But it is an exception to the “is” and “are” rules because as a COLLECTION it is used in common speech as a singular: “Dave’s pornography collection IS getting huge.” Not “are”.

  7. Sean -  July 15, 2014 - 9:58 pm

    The apostrophe has important uses for denoting contractions and possession.. the using of it help us understand the writing.

  8. Andrew Davies -  July 14, 2014 - 11:54 am

    Not really relevant to the main topic, but I feel I must object to the use of “multiple” as an adjective in paragraph four. The word “multiple” is a noun. There are many suitable adjectives like “several” or “many”.

  9. Translator -  July 14, 2014 - 1:23 am

    Many people have difficulty with this punctuation mark

  10. Alpo -  July 11, 2014 - 8:38 am

    Yes, but this doesn’t explain why people try to pluralize everything with an apostrophe before the s. What is the plural of fox? Fox’s. The plural of fly? Fly’s, of course. Cow? Cow’s?! Yes, even regular nouns fall victim to this horror.

    • uz64 -  July 11, 2014 - 7:03 pm

      Yes, but this doesn’t explain why people try to pluralize everything with an apostrophe before the s.

      Eh… because if you know proper English, you *don’t*.

      “What is the plural of fox? Fox’s.


      “The plural of fly? Fly’s, of course.”

      Since when? It’s actually “flies”.

      “Cow? Cow’s?!”

      Wrong again. Cows. No apostrophe.

      “Yes, even regular nouns fall victim to this horror.”

      What? Judging by your post, I think you are heavily mixing up “plural nounss” with “possessive nouns,” and severely misunderstanding the English language as a result. You should just stop talking now, because all you are doing is spreading misinformation. In my opinion, NO: we should NOT dumb down our language just for people who fail to understand it (such as the parent poster whose topic I am replying to).

      • Blob -  July 15, 2014 - 5:22 pm

        Lol, YOU should stop talking now, uz64. Maybe you’re a little oblivious but it doesn’t explain why you can’t see that Alpo was pointing out common mistakes, not making them. He/she didn’t misunderstand English, you misunderstood the message.

        • bz69 -  July 17, 2014 - 8:19 pm

          no i think YOU should stop talking now, Blob. uz64′s post is clearly a satire of people who obsess and insult others over minor issues of grammar and spelling but have difficulty with the broad strokes of actually interacting with other human beings. you know, the kind of person who would be moved to tears by martin luther king’s “i have a dream” speech but would completely ignore his point and in fact INSULT HIM if they found one comma out of place in the text.

          or is your post some kind of even more sophisticated satire? if so, i humbly apologize.

          • Anne Ominous -  July 20, 2014 - 11:38 am

            Nobody should “stop talking”, but everybody SHOULD realize that Alpo’s comment was parody.

  11. Jennifer -  July 11, 2014 - 2:41 am

    I take exception to very suggestion that we should do away with the apostrophe just because it’s confusing to some. In America especially, there seems to be a trend toward lowering standards over elevating awareness and education. I can accept this in many contexts, if grudgingly, but when it comes to our written language I draw the line. I’ve heard it argued that since language is the vehicle of culture, American English should reflect us as we truly are from generation to generation. I’d say we cover that well enough with our colloquialisms, not to mention that we shouldn’t want to look like we’re simply devolving as a civilization. Eliminating a form of punctuation would affect academic writing and the way we formally record our history, too. Nope. Our punctuation should be left alone.

    I’m still recovering from last year’s inclusion of “badassery” in the OED.

    • no offense but -  July 17, 2014 - 7:30 pm

      well jennifer, what’s interesting is that no one cares about your opinion. that’s exactly why language is so beautiful! the english language is larger than you or me, jennifer. it’s something we’ve all cooperated together for centuries to create.

      but the really interesting thing is, i bet if someone we “did away with” the apostrophe you’d keep using it, right? and so would a lot of people. i probably would too, if only out of habit. but even as each group decried the other as “devolved” or “really uptight about something that doesn’t matter,” we’d still each understand what the other has to say!

      pretty neat, huh? and you’d sacrifice all that for a damn apostrophe. ””””””””””””””””””””””””””””””””””””””””””””””’

      • Anne Ominous -  July 20, 2014 - 11:44 am

        “Well, Jennifer, what’s interesting is that no one cares about your opinion.”

        Except that we do. So you are proven wrong.

        There is a reason why languages have (and need) standards. While many things (Jennifer’s colloquialisms) do change with time, basic grammar and punctuation are remarkably tenacious and change only very slowly, over many hundreds of years.

        To excuse poor grammar and punctuation as “the new generation’s way of doing things” is to admit to a poor education. It’s that simple.

      • Japster -  July 21, 2014 - 9:49 pm

        Here’s the problem, no offense but, with your reasoning. Let’s just take a look at your post and Jennifer’s. We’d be forced to either do away with some contractions and possessives or have serious communication issues. I’d or Id, We’re or Were, year’s or years, it’s or its, we’d or wed – Just think how many words’ meanings change drastically without an apostrophe. Could we get used to it and figure it out? Probably, but the point of the rules and symbols and spelling and grammar and everything else about language is so that it’s easier to communicate, not more difficult. Someone more clever than I could probably find some confusions that would come from doing away with the apostrophe. If we didn’t have it we would need it and that is why we should keep it. Some of the ways it’s used might need to be adjusted, however.

  12. Amish -  July 11, 2014 - 1:28 am

    I do not quite agree with the use of the ‘s to mark plurals of letters as you have suggested in the last part ‘as in p’s and q’s, two A’s and four B’s, etc.’

    I could be wrong but plurals use a simple s as in two As, four Bs, and not an ‘s.

    • David -  July 12, 2014 - 6:32 pm

      Yes, I questioned this as well. Didn’t sound right. When one makes reference to a decade (such as the 1960s), no apostrophe is added, so why would it be done with letters? To avoid confusion in case the result looks like a word, as it would in the case of “As”?

    • Anne Ominous -  July 20, 2014 - 11:51 am

      An online English primer from Perdue recommends this use for ONLY lowercase letters. Their reasoning is apparent: when you are using uppercase letters, like BEM, making it plural is as easy as adding “s”: BEMs.

      But that is not the case with lowercase letters: as, bs, cs. So Perdue claims it is acceptable to use apostrophes there… but does not really say why it justifies breaking the clear rules that apply to all other cases.

      Most (not just a small majority, but a vast majority) of references reject Perdue’s reasoning, and say that apostrophes may NOT be used to designate plural, at all, ever.

  13. Ash Gii -  July 9, 2014 - 7:54 pm

    And no, I think the apostrophe has important uses for denoting contractions and possession, so even though it can be confusing, the process of using and interpreting the apostrophe helps us understand our writing.

    • Scia -  July 10, 2014 - 10:30 am

      Agreed. There have been times where I’ve found the apostrophe incredibly useful in clarifying possession. I’ve also had conversations about accents, and it can be useful for indicating omitted sounds (e.g. “mountain’ turning into “moun’in”). And these are just a couple of the ways it’s come in handy for me.

      At any rate, I don’t think the apostrophe is leaving anytime soon.

  14. Ash Gii -  July 9, 2014 - 7:48 pm

    I read that the use of the apostrophe to signify possession is not, in fact, a separate grammatical phenomenon from that of using them to signify letter omission, because the ending ‘es’ used to, in addition to indicating plurality, indicate possession. The apostrophe (replacing the ‘e’) was then employed in order to distinguish possession from plurality. Has anyone else heard or learned this?

    • Leland -  July 15, 2014 - 2:38 am

      The Wikipedia on “English possessive” states:

      Nouns, noun phrases and some pronouns generally form a possessive with the suffix -’s (or in some cases just by adding an apostrophe to an existing -s). This form, particularly in English language teaching, is sometimes called the Saxon genitive, reflecting the suffix’s derivation from a genitive case ending in Old English (which in older scholarship was known as Anglo-Saxon).


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