Sisters vs. Sister’s – Which is Correct?

“Sisters” is the plural of “sister,” referring to two or more female siblings. “Sister’s” is singular possessive, meaning something belonging to one sister, or a contraction of “sister is” or “sister has.” Choose “sisters” for more than one sibling and “sister’s” for possession or contraction. The apostrophe changes meaning and function.

Sisters or Sister’s – Which is Correct?

Both sisters and sister’s are correct American English words, but they serve different grammatical purposes. Sisters is the plural form of sister and means two or more female siblings. Sister’s can show that something belongs to one sister, or it can shorten “sister is” or “sister has.”

The Best Trick to Remember the Difference

Use the apostrophe as a clue. If you mean more than one sister, use sisters with no apostrophe. If you mean something belonging to one sister, use sister’s. You can also expand sister’s into “sister is” or “sister has” to test whether it is a contraction.

Word	Part of Speech	Meaning	Example
sisters	Plural noun	Two or more female siblings	My sisters live in different cities.
sister’s	Possessive noun or contraction	Belonging to one sister; “sister is” or “sister has”	My sister’s coat is blue. / My sister’s arriving soon.

How to Use Sisters

Sisters is the regular plural noun for sister. Use it when referring to two or more female siblings. It can also describe women connected by a close bond, shared identity, religion, organization, or cause. The word is suitable in casual, formal, and literary writing.

Example 1: The sisters opened a bakery together.

Example 2: Three sisters performed at the community concert.

Example 3: The organization brought sisters from different backgrounds together.

What are the different forms of Sisters?

Sisters is the regular plural form of sister. The singular form is sister, while the plural form is sisters. When showing possession by more than one sister, use sisters’, with the apostrophe after the s: The sisters’ house was renovated.

Do not use an apostrophe simply to make sister plural. Sisters is correct for multiple siblings, while sister’s indicates singular possession or a contraction.

Etymology of the word Sisters

Sister comes from Old English sweostor, related to similar words in other Germanic languages, including Old High German swester and Old Norse systir. The plural ending -s developed as part of the standard English system for forming regular plurals.

How to Use Sister’s

Sister’s has two main uses. First, it is the singular possessive form of sister, showing that something belongs to or is associated with one sister. Second, it is a contraction of either sister is or sister has. The surrounding sentence usually makes the meaning clear.

In possessive use, sister’s comes before a noun or noun phrase: my sister’s bicycle. As a contraction, it is often followed by an adjective, adverb, present participle, or past participle: My sister’s tired, My sister’s leaving, or My sister’s finished her work.

Example 1: I borrowed my sister’s jacket.

Example 2: My sister’s preparing dinner tonight.

Example 3: My sister’s already completed the application.

What are the different forms of Sister’s?

Sister’s can represent three related grammatical ideas. As a possessive noun, it means “belonging to one sister,” as in the sister’s room. As a contraction of sister is, it appears in sentences such as My sister’s happy. As a contraction of sister has, it can appear before a past participle, as in My sister’s finished the project.

For possession by multiple sisters, use sisters’, not sister’s. For the plural noun without possession, use sisters.

Etymology of the word Sister’s

Sister’s combines the Old English-derived noun sister with the possessive apostrophe and s. The apostrophe became a standard written marker of possession over time. In contractions, the apostrophe indicates letters omitted from is or has.

Related Concepts

Understanding plural nouns, possessives, and contractions makes the difference between sisters and sister’s much easier to recognize.

• Plural nouns: A plural noun refers to more than one person, place, thing, or idea. Most regular English nouns form the plural by adding -s, as in sister becoming sisters.
• Possessive nouns: A possessive noun shows ownership, association, or connection. A singular noun usually forms its possessive with an apostrophe and s, as in sister’s book.
• Contractions: A contraction combines words by omitting letters and replacing them with an apostrophe. Sister’s can shorten either sister is or sister has.
• Plural possessives: A plural noun ending in -s generally forms its possessive by adding only an apostrophe. For example, sisters’ room means a room belonging to multiple sisters.

Examples from Media and Literature

The distinction between sisters and sister’s appears frequently in stories, films, and news writing. These examples illustrate the correct forms in familiar contexts:

• Little Women: Louisa May Alcott’s novel focuses on the four March sisters, so sisters is used when referring to the group.
• Frozen: Anna and Elsa are sisters. A sentence such as “Anna searches for her sister’s castle” uses sister’s to show possession by one sister.
• Cinderella: The stepsisters are multiple characters, so sisters is appropriate when discussing them together.
• The Sound of Music: A sentence such as “The sister’s song begins softly” uses sister’s if one particular nun or female sibling is being identified as the person connected with the song.
• News writing: A report might say, “The sisters launched a charitable foundation,” while “The foundation bears their sister’s name” refers to one sister’s name.

Practice Exercises

Choose the correct word to complete each sentence: sisters or sister’s.

1. My two ______ are visiting this weekend.
2. I accidentally took my ______ umbrella.
3. My ______ studying for her final exam.
4. The three ______ started a business together.
5. My ______ already finished the book.

Answer Key

1. sisters — The sentence refers to two siblings.
2. sister’s — The umbrella belongs to one sister.
3. sister’s — This means “sister is studying.”
4. sisters — The sentence refers to three siblings.
5. sister’s — This means “sister has already finished.”

Sisters Synonyms

Synonym	Definition
female siblings	A precise phrase for two or more girls or women who share at least one parent.
siblings	Brothers or sisters; this term does not specify gender.
kin	Family members or relatives; a broader and sometimes more formal term.
sisterhood	A relationship or bond among sisters or women with a shared identity.

Sister’s Synonyms

Synonym	Definition
belonging to a sister	A direct equivalent when sister’s expresses possession.
her	A possessive determiner that can sometimes replace a phrase such as “the sister’s.”
sister is	The expanded form of the contraction in sentences such as “Sister’s ready.”
sister has	The expanded form of the contraction in sentences such as “Sister’s finished.”

Frequently Asked Questions

Question 1: Is “sisters” or “sister’s” correct for more than one sibling?
Sisters is correct for more than one sibling. The word does not need an apostrophe because it is simply the plural of sister.

Question 2: When should I use “sister’s”?
Use sister’s for possession by one sister, as in my sister’s phone. You can also use it as a contraction of sister is or sister has, as in my sister’s calling or my sister’s arrived.

Question 3: What is the difference between “sister’s” and “sisters’”?
Sister’s shows possession by one sister. Sisters’ shows possession by two or more sisters. For example, the sister’s car belongs to one sister, while the sisters’ car belongs to multiple sisters.

Question 4: Is “sister’s” always possessive?
No. It can be possessive, but it can also be a contraction of sister is or sister has. Replace it with both expanded phrases to determine which meaning fits the sentence.

Conclusion

Use sisters when referring to two or more female siblings. Use sister’s for something belonging to one sister or as a contraction of sister is or sister has. Use sisters’ for possession by multiple sisters. Pro Tip: Checking apostrophe placement helps protect your credibility and professional reputation in formal writing.