How to Use the Apostrophe (Single Quotation Mark) in English

Use the apostrophe to show possession with proper nouns. The apostrophe 's' following a proper noun indicates that the person, place, or thing owns what follows its name. For example, "Mary's lemons" (the lemons belonging to Mary). We know the lemons belong to Mary because of the s that comes after her name. Other examples include "China's foreign policy" (the foreign policy of China) and "the orchestra's conductor" (the conductor of the orchestra).

• The possessive form of certain proper nouns requires careful consideration. For instance, "Sunday's football game" is logically incorrect (since Sunday can't possess anything), but it is widely accepted in both spoken and written language. Similarly, "A hard day's work" is perfectly acceptable even though a day (day) cannot literally own something.

Ensure Consistency When Using the Apostrophe After Words Ending in 's'. When a name ends in 's', you may use the apostrophe without adding another 's' to indicate possession. However, linguists from the Chicago Writing School and others suggest adding 's' after the apostrophe.

• Note the differences in usage:
  
  • Acceptable: Jones' house; Francis' window; Enders' family.
  • Recommended: Jones's house; Francis's window; Enders's family.
• Regardless of the style you choose, be consistent with its use. The style you apply doesn't matter as long as it is used consistently throughout your writing.

Avoid Using the Apostrophe for Possession with 'it'. While "China's foreign policy" is not incorrect, if your readers understand that you're referring to China as 'it', you should use "its foreign policy" to indicate possession.

• This helps avoid confusion between "its" for possession and "it's" as the contraction for "it is." If you're unsure about using the apostrophe, try replacing it with "it is" or "it has." If the sentence doesn't make sense (for example, "it is foreign policy" cannot replace "China's foreign policy"), then omit the apostrophe.

Use the Apostrophe to Indicate Possession with Plural Nouns. A common mistake when using the apostrophe with plural nouns is when referring to a family's possession. For example, the Smart family lives across from you and they own a boat. The boat is "the Smarts' boat," not "the Smart's boat." Since you're referring to all members of the Smart family, you should start with "Smarts." Since the whole Smart family owns the boat, the apostrophe is added after the 's'.

• If the family name ends in 's', make it plural before adding the apostrophe. For example, if you want to refer to the Williams family, the plural form of their surname would be written as "the Williamses." If you want to refer to their dog, you would write "the Williamses' dog." If their surname is hard to pronounce or inconvenient, simply refer to them as "the Williams family" and "the Williams family's dog."
• If you're listing individuals who jointly own something, you need to know where to place the apostrophe. For example, if both John and Mary own a cat, you would write "John and Mary's cat" — not "John's and Mary's cat." "John and Mary" is a compound noun, so only one apostrophe is needed.

In General, Avoid Using the Apostrophe for Plurals. Incorrectly using the apostrophe for plural nouns is known as the greengrocer's apostrophe, as grocers make the most noticeable mistakes. If you have more than one apple, the correct form is "apples'", not apple's.

• One exception to this rule is when writing the plural of a letter. Therefore, Why are there so many i's in the word "indivisibility"? is correct, depending on who you ask. It's simply for clarification, so the reader doesn't confuse it with the word "is." However, in modern usage, people tend to avoid adding the apostrophe and instead place the letter in quotation marks before pluralizing it: Why are there so many "i"s in the word "indivisibility"?
• Avoid issues with small numbers by writing them in words: "ones" instead of "1's," "fours" instead of "4's," or "nines" instead of "9's." Numbers should only be written as words if they are ten or less.

Understand the Use of Apostrophes with Abbreviations and Years. For instance, if you have the abbreviation 'CD', to make it plural, write "CDs", not "CD's". The same applies to years — instead of writing "Spandex was popular in the 1980's", write "1980s".

• The only time an apostrophe should be used with years is when it's substituting omitted digits. For example, to abbreviate the year 2005, you can write '05. In this case, the apostrophe acts like a contraction, serving the purpose of shorthand.

Using the Apostrophe for Contractions. Especially in informal writing, the apostrophe is used to indicate one or more missing letters. For example, "don't" is a contraction for "do not"; other examples include "isn't," "wouldn't," and "can't." Contractions can also be used with the verbs "is," "has," and "have." For instance, you can write "She's going to school" instead of "She is going to school"; or "He's lost the game" instead of "He has lost the game".

Be Careful Not to Confuse 'its' and 'it's'. The apostrophe in "it" is used for contractions of "it is" or "it has." It is a pronoun, and pronouns have their own possessive forms without an apostrophe. For example, "That noise? It's just the dog eating its bone." It may seem complex, but it follows the possessive pronoun rule: his, hers, its, yours, ours, theirs.

Avoid Using Nonexistent Contractions. Many people use informal contractions such as "shouldn't've" or "'ought." These contractions are incorrect and should be avoided in formal writing. Another mistake to avoid is using a person's name in a contracted form. For example, using "Bob's" as a contraction for "Bob is" is wrong. "Bob's" is considered a possessive, not a contraction. However, contracted pronouns such as "he's" or "she's" are correct.

When writing in cursive, always connect the letters following the apostrophe to the rest of the word. For example, when writing the word she's, you write shes first, then add the apostrophe afterwards.

• If in doubt, always remember that apostrophes are most commonly used in nouns to indicate possession. Avoid using apostrophes in other situations.
• For singular names ending in "s", the Chicago Manual of Style suggests placing the "s" after the apostrophe, such as in "Charles's bike". If your assignment requires a specific writing convention, adhere to it. As long as that convention is consistent throughout the text, you can use either form mentioned.
• The book The Elements of Style by Strunk and White is a concise and helpful guide on writing and punctuation. It's a handy reference you can keep with you if you're uncertain about any writing rules.

• When a word ends with "y," such as in "try," be mindful when converting the verb form. For example, "try" should not be written as "try's." The correct form is "Tries".
• Using an unnecessary apostrophe shows a lack of understanding of the rules for possession, contractions, and plurals. If unsure, the safer option is to omit the apostrophe.
• Do not use apostrophes or quotation marks for emphasis. For instance, take a billboard that says: Joe Schmo, the "best" realtor in town! (This makes the word "best" sound sarcastic rather than emphasizing it.)
• Never place an apostrophe inside names on an address label. If your last name is "Greenwood," "The Greenwoods" is correct, while "the Greenwood's" is incorrect. "The Greenwoods" indicates that it refers to a household of people with the same last name, not possession.
• Never write "Her's." "Her's" is not a valid word, just as "him's" is not. Remember that possessive pronouns do not require apostrophes: his, hers, its, yours, ours, theirs.