Form the plural with proper nouns simply by adding s or es. Note that there is no need for an apostrophe.

When forming the plural of a name like Suzy, simply add s. Don’t change the y to ies, since doing so changes the original word.

Use s or es alone, without an apostrophe, when forming the plural of a family.

To make an uppercase letter used as a word plural, add an s.

To make an italicized lowercase letter used as a word plural, add an s.

There is no need to include an apostrophe before the s when making numerals plural. Simply add an s.

To make a quoted phrase plural, add an apostrophe plus s inside the quotation marks.

Make capitalized abbreviations plural by simply adding an s.

Make most truncated or letters-omitted abbreviations plural by adding an s before the period.

To make plural an abbreviation that has two or more periods, use an apostrophe and s.

Some plurals are tricky, but the application of common sense will do the trick in most cases. For example, is mother-in-laws or mothers-in-law correct? We’re talking about more than one mother, not more than one law, so the latter is right. When in doubt, consult a dictionary.

If a word ends in an unpronounced s, make it plural by ignoring it—don’t add an s, an apostrophe, or anything else.