The other day, one of you asked me a great question about a particular day or event and whether it required an apostrophe. It wasn’t the Farmers Market or Veterans Day, but here’s an explanation similar to the one I gave, and it mentions how to handle different holidays. From GrammarBook.com:
Do You Use an Apostrophe When Spelling Father’s Day?
The most direct answer is yes. The Chicago Manual of Style (CMOS) and The Associated Press Stylebook list the following holidays as singular possessives: Mother’s Day, Father’s Day, New Year’s Eve, New Year’s Day, St. Patrick’s Day.
CMOS uses the plural possessive for Presidents’ Day, while AP writes Presidents Day. Both agree on no apostrophe in Veterans Day.
We have heard from readers who object to the apostrophe in Father’s Day because it implies one father. There are several scenarios in which a person can have two fathers: a father and stepfather, a biological father and adopted father, or a child being raised in a home with two fathers. The same can be true of two mothers.
Our post Apostrophes and False Possessives discusses how in English, nouns become adjectives all the time. If you think of the word Fathers as an adjective describing the word Day, then you would not use an apostrophe. It would be a day for fathers. The same could be said for using the plural possessive Fathers’ Day. It is a day belonging to all fathers.
No matter how many dads you have, according to our style guide it is still Father’s Day with the apostrophe. Don’t forget to give your dad a call, send him a card, or take him out to breakfast, if you can. If he’s not around anymore, take yourself out for breakfast and raise a cup of coffee or a mimosa to the man!
Kara Church
Pronouns: she/her
Technical Editor, Advisory
Editor’s Corner Archives: https://episystechpubs.com/
Editor's Corner 
Leave a Reply