The Associated Press Stylebook recommends just an apostrophe: It's Tennessee Williams' best play. But most other authorities endorse 's: Williams's. Williams's means “belonging to Williams.” It is not the plural form of Williams. People's names become plural the way most other words do.
First, make the noun Williams into a plural: Williamses. Then add the possessive apostrophe according to the rules that gave us “the cats' tails.” That gives us “We had dinner at the Williamses' house last year.”
The Associated Press Stylebook says the correct way to write the possessive case of Chris is Chris', not Chris's. Other style guides, including the Chicago Manual of Style, say Chris's is correct. If there isn't a specific guidebook you need to follow, you can use either Chris' or Chris's.
Second, a name ending in s takes only an apostrophe if the possessive form is not pronounced with an extra s. Hence: Socrates' philosophy. Saint Saens' music.
Explanation: Plural words which do not end in the letter 's' have the apostrophe before the 's' when showing possession. Example: She is the children's writer; she is the people's princess. Example words: James, Wales, Paris and Dickens. Commentary: both James' birthday and James's birthday are grammatically correct.
To form the possessive of a noun that ends in S, AP style has separate rules for proper names and generic nouns. For proper names like James, AP says, add an apostrophe only: He borrowed James' car. For generics like boss, add an apostrophe plus S: He borrowed the boss's car.
Both James' and James's are grammatically correct.
Certain academic writing styles prefer one version over the other, but it doesn't matter which one you use in your regular, written English.
Only use an apostrophe when you want to make a name possessive. ("From The Smith's" is always wrong, but "The party is at the Smiths' house" is correct.)
The plural of Jones is Joneses, ‐es being added as an indicator of the plurality of a word of which the singular form ends in s, as in dresses or messes. The apposition of the much misused apostrophe to the word Jones does not pluralize it.
The important thing to remember is that Thomas is singular. When you're talking about more than one, you first form that plural by adding -ES. One Thomas, two Thomases. Then, to note that something is owned by more than one Thomas, just take the plural and make it possessive: Thomases'.
The possessive
Quick Use: Use an apostrophe + s for singular nouns (sea, sky), common nouns ending with s (tigress, mistress), and irregular plural nouns (women, children). Use only the apostrophe for proper nouns ending with s (Tess, Jesus, Texas) and regular plural nouns (cars, protestors).
This is Travis's house. (correct and sounds better) This is Travis' house. (correct but awkward-sounding)
According to the Chicago Manual of Style (which folks in my profession refer to as the Bible of Book Publishing), the rule is the same as any other singular possessive. You write her name with possession just like you say it: Alexis's. (Yes, I know it looks funny to those of us who aren't editors.)
If the name ends in s, z, ch, or sh, you need to add es. That means the Davis family becomes the Davises, the French family becomes the Frenches, the Hernandez family becomes the Hernandezes, and the Glaves family becomes the Glaveses. If the name ends in x, also add es—unless the x is silent.
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.
Use 's for the possessive of singular nouns that end in s:
Charles's books, Dickens's novels, actress's script. Note: If a singular noun ending in s is followed by a word beginning with s, use only the apostrophe, not the 's. For example, Charles' shirt.
According to English style guides, singular possessives are formed with –'s and plurals with just an apostrophe, so the possessive of the singular Jones is Jones's and of the plural Joneses is Joneses'.
Use an apostrophe before the “s” to show singular possession (something belonging to one person). Note: Although names ending in s or an s sound are not required to have the second s added in possessive form, it is preferred. To show plural possession, form the plural of the noun and then add the apostrophe.
First, form your plural: You're visiting the Rosses. Then make it possessive: You're going to the Rosses' house. Remember, because this is plural, there's no dispute on how to make it possessive. Use just an apostrophe.
Remember: the only time you add an apostrophe to a last name is if you are making your last name possessive. For example, "That is the Gamels' house on the corner." Thanks for reading!
When making your last name plural, you don't need to add an apostrophe! The apostrophe makes the name possessive. The last letter of your last name will determine if you add an “-s” or an “-es”. If your last name ends in -s, -z, -ch, -sh, or -x, you add -es to your last name to make it plural.
You usually make family names plural by adding an “s” to the end. However, if the name ends in "s," “x,” "z," “ch,” or “sh,” you usually add an “es” instead (but there are exceptions). The plural of “mother-in-law” is “mothers-in-law.”
The possessive of a singular noun is formed by adding 's (whatever the final consonant). Note that some consider Jesus to be an exception to this rule and insist that its possessive be written Jesus'; other exceptions may include other ancient proper names.
Jameses is the plural form of James.
Usually when nouns end in S we add -es to pluralize them.
Like any noun ending in S, the plural adds -ES, so one James, two Jameses. For possessive, just add an apostrophe: Jameses'. This formation common for last names (“keeping up with the Joneses' spending habits”) but can also be used for first names.