11 Dec A Grammar Blog

A recent New Yorker cartoon has a teacher hovering over a child’s Mother’s Day card.  The card reads “Happy Mothers’ Day”.  The teacher is pointing to the proper place of the apostrophe: between the r and the s.  The child says, “I have two mommies.  I know where the apostrophe goes.”

The child is right: if the possessive noun is plural, the apostrophe goes after the s.  So: if you have one mother (that is, singular), the apostrophe goes before the s–  “Happy Mother’s Day”.  If you have two mothers,  the apostrophe goes after the  s–“Happy Mothers’ Day”.