- The horse's hay
- The horses' hay
For one horse (or one possessor), put the apostrophe before the s. For more than one horse (or more than possessor), put the apostrophe after the s.
(Beware! There are some exceptions to this rule.)
Apostrophes Are Used to Show PossessionAn apostrophe and the letter s are often used to show possession.
When using an apostrophe to show possession, the very first thing you have to think about is whether the possessor is singular or plural. This is important because it determines where your apostrophe goes. Look at these examples (the possessors are shown in bold):
With a Singular Possessor, the Apostrophe Goes before the sSo, with one possessor, the apostrophe goes before the s.
With a Plural Possessor, the Apostrophe Goes after the sWith a plural possessor, the apostrophe goes after the s.
An Exception to the Rule (Plural Nouns Not Ending s)
Mistakes with apostrophes to show possession are very common. One reason for this is the number of exceptions to the rules above. For example, plural words which do not end in the letter s (e.g., men, people, children) take the apostrophe before the s when showing possession.
Exception to the Rule (Singular Nouns Ending s)To make things even more complicated, singular words which end in s (e.g., Charles, Wales, Paris, Dickens) can end in ' (i.e., just an apostrophe) or 's when showing possession.
Charles' or Charles's pal (both correct)
Les' or Les's wife (both versions correct)
Both Charles' birthday and Charles's birthday are grammatically correct. However, as a guideline, you should use the version which best matches how you would pronounce it. In other words, use Charles's if you pronounce it "Charlesiz", but use Charles' if you pronounce it "Charles".
Exception to the Rule (Compound Nouns)Here is another quirk. Some compound nouns (e.g., sister-in-law) do not form their plurals by adding s to the end. The s is appended to the principal word (i.e., the plural is sisters-in-law). With a noun like this, the possessive form is created by adding 's to the end, regardless of whether it is singular or plural.
Read more about forming the plurals of compound nouns.
Apostrophes with Joint OwnershipFinally, joint ownership is shown by making the last word in the series possessive. Individual ownership is shown by making both (or all) parts possessive.
(Note: both parts are possessive)
(Without context, it will be assumed that Andrew has one factory and Jacob has one factory. Another construction is required if this is not the case:
"Andrew's factories and Jacob's factories" is one option.)
GENERALLY, THE RULING IS:
BEFORE FOR SINGULAR
AFTER FOR PLURAL
Singular possessor? Put your apostrophe before the s:
Where to put the apostrophe is only determined by the possessor. It doesn't matter one jot whether the thing being possessed (in the examples above, dinner or dinners) is singular or plural.
THE RULES ARE COMPLEX, BUT NEVER PUT AN APOSTROPHE IN THE WORD ITSELF
An apostrophe that shows possession never appears inside the word itself.
(For one "cat", this would be correct.)
It's is a contraction of it is or it has.
This is a 100% rule. The word it's has nothing to do with possession. The word its (without an apostrophe) is used for possession.
(This should be its.)
The apostrophe error with plurals
Apostrophes in time (temporal) expressions
Apostrophes replace letters
Apostrophes to show the plural of abbreviations
Mother's/Mothers' Day, Father's/Fathers' Day, Veteran's/Veterans' Day, Manager's/Managers' Meeting, Chief Executive's/Chief Executives' Meeting