Dictionary.com Word FAQs
How do I write the plural of an italicized word? How about words in quotation marks?
For plural forms of italicized or underlined words, phrases, abbreviations, and letters, the s or 's is almost always roman: "a row of x's," "7's sometimes look like 2's, "there are thee's and thou's in older literature," "too many New York Times." The apostrophe and s are not italicized or underlined. A title already in plural form may be left unchanged, e.g., two Chicago Tribunes. Foreign words in their plural form should be set entirely in italics, e.g., señores. The plural of a word or phrase in quotation marks may be formed by adding an apostrophe and an s, with the closing quotation marks following the s: How many more ok's can he use in a conversation? A plural ending should never follow closing quotation marks. A better option is to reword.