Apostrophes have two basic uses, the oldest of which is to indicate missing letters and numbers.
For example, cannot may be contracted to can’t by showing where no has been removed, and 2005 may be shortened to ’05 by showing where 20 has been removed.
The simple rule is place an apostrophe where a letter or letters or a set of numbers are omitted.
Thus, rock and roll becomes rock ’n’ roll because the a and d are removed from and. Note the rule requires apostrophes on both sides of the lone n (never rock n’ roll or rock ’n roll—although rock an’ roll follows the rule).
She was a child of the 1960s becomes She was a child of the ’60s (never a child of the 60’s).
It was may be contracted to ’twas, as in the night before Christmas (never t’was).
It is may be contracted to it’s (never its’ ). Remember its without an apostrophe is a possessive pronoun—they never use apostrophes: his, yours, hers, its, theirs (never hi’s, your’s, her’s, it’s, their’s).
Nautical forecastle becomes fo’c’s’le.
Another “never” is apostrophes aren’t used to make plurals, such as hat’s for sale or banana’s are cheaper by the bunch.
We’ll review an editor’s (possessive) take on other uses of the apostrophe another time.