The correct use of an apostrophe is either to form a possessive or a contraction.
- Possessive: the teacher’s sign, a person’s signature, your foot’s toe
*The only possessives that do NOT use the apostrophe are pronouns:
his, hers, its, theirs, whose, theirs, yours, ours
- Contraction: don’t, isn’t, can’t
You will also find the apostrophe used when letters have been removed: rock ‘n’ roll, or when a plural would be misread: do’s and don’ts (It would be awkward to read “dos” and don’ts.).
For common acronyms or abbreviations that are typically capitalized, do not use an apostrophe to form the plural. Just add an s: DVDs, CDs.
Please, I’m begging here, do NOT use the apostrophe to form the plurals of nouns:
If you can find other examples of incorrect apostrophe use, and they’re everywhere so this should be an easy assignment, please post them here for our pleasure (or pain).
A necessary point of clarification here: Its is the possessive pronoun (Example: “The apostrophe is losing its meaning.”). It’s means it is (Example: “It’s not that hard!”).