When we were young, we spent much time in school, starting in elementary all the way through high school, learning how to write. This included basics of spelling and grammar. Somewhere along the way, however, we often forget some of these lessons. One of the places where this is increasingly evident than in the formation of plurals and possessives.

Think back to your school days. How do we turn a word from the singular form to the plural? The answer is very simple. We add the letter s to the end of the word, or the letters es if the worn already ends in the letter s. For example:

  • Mansion becomes Mansions
  • House becomes Houses
  • Christmas becomes Christmases

Nouns ending in f or fe change the f to a v and the plural ends in an es. If the noun ends in a consonant followed by the letter y, the y changes to an ie before the s. If it ends in a vowel and a letter y, simply add the letter s. The exception is proper nouns, where the letter y is always followed by an s (e.g., Tonys, Emmys, etc.).

To make a possessive, one adds an apostrophe and the letter s after a word (or just an apostrophe if the word already ends in the letter s). Examples include:

  • John’s pencil
  • The dog’s bed

Proper nouns, including the names of families, never use an apostrophe unless one is referring to something owned by that family.

  • The Morins (referring to member of the Morin family)
  • The Holmeses (referring to members of the Holmes family)
  • The Morin’s house
  • The Holmes’s car

The same holds true for decades. One writes “the 1920s” or “the 50s” never “the 1920’s” or “the 50’s.”

There are, of course, some exceptions to the above rules, but not to the rule about that plurals are never used for plurals, only for possessives. For more help on this subject, see Bryan A. Garner. The Chicago Guide to Grammar, Usage, and Punctuation (Chicago: University of Chicago Press, 2016) 23–29.