The primary use of the apostrophe is to show possession.
To Indicate the Possessive Case of Singular Nouns
To create a possessive singular noun, add an apostrophe + “s” to the end of a singular noun or indefinite pronoun.
To Indicate the Possessive Case of Plural Nouns
To create a possessive plural noun, just add an apostrophe. There is no need to add an additional “s.”
Irregular nouns are nouns that are made plural by changing their ending, rather than adding “s.” In the case of irregular plurals, add an apostrophe + “s” to show possession.
To Form Contractions
A contraction is a word by combining two words. Some letters are taken out and replaced by an apostrophe. Here are some examples of contractions:
Possessive pronouns are the possessive forms of personal pronouns, and include “his,” “hers,” “theirs,” “whose,” “yours,” “ours,” and “its.” These show possession and do NOT require an apostrophe. Be careful to not confuse possessive pronouns with contractions.
With a Non-Possessive Plural
Just because a noun ends in an “s” does not mean it is possessive. If there is no possession indicated, do not add an apostrophe.
✗ The doctor’s walked into the clinic.
✓ The doctors walked into the clinic.
✗ The Jones’ family was having a reunion.
✓ The Jones family was having a reunion.
With a Possessive Pronoun
Do not add an apostrophe to a possessive pronoun, since possessive pronouns, by definition, already show possession.
✗ The new toy she picked up wasn’t her’s.
✓ The new toy she picked up wasn’t hers.
✗ The big house on the corner was their’s.
✓ The big house on the corner was theirs.