Follow the rules below for forming words to show more than one of the things named:

• For most words, add s: books, guitars. Except when making a plural of single letter, do not add an apostrophe to words or numbers to make them plural.
• Add s to compound words written as single words: cupfuls, handfuls. For compound words that use separate words or link the words with a hyphen, make the most significant word plural: assistant attorneys, attorneys general, daughters-in-law, deputy chiefs of staff.
• Add s to figures: General Motors built the car in the 1940s. The Boeing Co. sold 12 more 767s.
• Don't change the spelling of proper nouns when making them plural. Add es to most proper names ending in es or z: Gonzalezes, Jameses, Joneses, Parkses. Add s to other proper names, including most proper names ending in y even if preceded by a consonant: the Clintons, the Abernathys, not the Abernathies.
• Add es to most words ending in ch, s, sh, ss, x and z: churches, buses, foxes, fuzzes, glasses.
• Change is to es in words ending in is: parentheses, theses.
• Add es to most words ending in o if a consonant precedes o: echoes, heroes. There are exceptions: pianos.
• Words with Latin roots: Change us to i in words ending in us: alumnus, alumni. Change words ending in on to a: phenomenon, phenomena. Add s in most words ending in um: memorandums, referendums but not addenda, curricula, media.
• Avoid using a possessive name as a plural: The free passes are available at four McDonald's restaurants. Not: The free passes are available at four McDonald's.
• Do not use 's when writing about words as words: His speech had too many ifs, ands and buts.
• To avoid confusion, add 's to single letters: Dot your i's. She earned two A's and three B's on her report card. Add s to multiple letters: He knows his ABCs. They have three color TVs.