I stopped by a "vision center" today to get my eyeglasses fixed. While waiting, I noticed the signs above the eyeglass frame displays. They said "Mens" and "Womens."
Maybe the apostrophes just wouldn't fit on the signs, which should have said "Men's" and "Women's." Or maybe the signmaker didn't have apostrophes.
Here's an illustration of why the signs needed apostrophes:
Man = singular noun
Woman = singular noun
Men = plural noun
Women = plural noun
Man's = singular posssessive (that man's glasses)
Woman's = singular possessive (that woman's glasses)
Men's = plural possessive (many men's glasses)
Women's = plural possessive (two women's glasses)
Mens = incorrect word
Womens = incorrect word
If you are having a sign made, make sure your signmaker uses apostrophes for possessive forms. Or try this approach: "Frames for Men" and "Frames for Women."
You may be wondering whether I mentioned the missing apostrophes to the staff at the vision center. No, I don't want to be rude. If they had asked, of course, I would have shared the rules.