“Poor grammar” by Lyndi and Jason is licensed CC BY SA-2.0.
The problem with the apostrophe is that it has some conflicting tasks: it is used primarily to show possession, mark contractions, and, minimally, to show plurals. But people have gotten it all mixed up. Apostrophes now seem to be scattered at random on storefront signs and all over the internet. A scant two to three hundred years ago, people didn’t even use apostrophes (yes—a world without apostrophes!). But the thing does add precision to writing; it does prevent confusion. The rules are stupidly simple.
WHEN TO USE APOSTROPHES
TO Show possession for singular words not ending in s
Add ‘s to the word.
- Earth’s shadow
- India’s population
- that fish’s ear
- this company’s profits
to Show possession for singular words ending in s
Add ‘s or just add the apostrophe after the s. (Usage varies on this.)
- Venus’s orbit (or Venus’ orbit)
- Mars’s shadow (or Mars’ shadow)
- James’s calculator (or James’ calculator)
to Show possession for plural words ending in s
Add an apostrophe to the plural form of the word (but don’t add another s).
- several planets’ orbits
- many countries’ populations
- these companies’ employees
to Show possession for plural words not ending in s
Add ‘s.
- women’s rights
- gays’ rights
- men’s rights
- people’s rights
- children’s education
- geese’s honking
to Show the plural of numbers or letters when they are discussed as such
Add ‘s. (Again, usage varies on this, but this is a safe choice.)
- On a computer, O’s are represented by O’s and 0’s with 0’s.
- She got all B’s on her report card.
- Do you know how many c’s and s’s are in the word ne_e__ary?
to create contractions
Insert an apostrophe in place of the letter(s) that are extracted from words to make contractions.
- Do not = don’t
- Is not = isn’t
- Will not = won’t
- Should not = shouldn’t
- Was not = wasn’t
- You all = y’all
*Note: Do not use apostrophes when referring to a decade in time.
the 1950s
the ’90s
*Note: Possessive pronouns don’t use the apostrophe. (I don’ t know who made this rule.)
This book is yours.
This website is theirs, not ours.
And, now, everybody’s personal favorite—the one that English instructors and copyeditors can spot from outer space—the rules for its and it’s.
Its is the possessive form of it. It’s is the contraction of it is.
its vs. it’s
The SGO density gauge is missing one of its adjusting knobs. It’s apparent the knob has been missing for some time.
The company is increasing its market share. If it continues on its current trajectory, it’s going to take over the entire market.
There are others rules involving apostrophes, such as for quotes within quotes, but we’ll leave those for the reference books or online grammar sites. The thing to remember about using apostrophes (and all punctuation for that matter) is this:
If you aren’t sure of the correct punctuation, take time to look it up. When you’re online, this takes very little time. We all make typos and grammar errors, but nothing says amateur like careless punctuation.
