JS Tip 422: Apostrophes, Part IV

From the Writing Workshops: Apostrophes, Part IV

We’ve been talking about apostrophes and possession. Last week, we promised to explore other uses of apostrophes.   

Use an apostrophe to form the plural of lower-case letters:

The play chart was filled with x’s and o’s.

Use no apostrophe to form the plural of other constructions:

An upper-case letter:

He promised a return to the three Rs.

An upper-case abbreviation:

They’ve gone through three CEOs in the last year.  

Numerals used as time periods:

The trend began in the 1990s.

But . . . 

If you decide to shorten 1990s, use an apostrophe to show the loss of the first two numbers:

The trend began in the ‘90s.

Hmm.

Interesting.

What are your questions? We love this stuff.