possessively possessed or “describingly” described

To be possessively possessed or “describingly” described—that truly is the question

Mother’s Day       Mothers’ Day       or Mothers Day?

My Word Processor’s default correction is: “Mother’s Day”

As I see it, there are maybe three options here:

1.       Mother’s Day = that at least one day out of every year is “owned” exclusively by my mother—of which, I’d gladly give her possession of any day she would like—if not all of them.

2.       Mothers’ Day = that one day out of each and every year has been set aside to be owned or “possessed” by all mothers—and again, why not give them (all mothers) ownership of ever day of our lives?

Note: my spell checker accepts both the single possession and the plural: I guess that it’s then a matter of preference—to give noted possession of one day of the year to one mother or all mothers in general.

Now of the third option—the one that I prefer—“Mothers Day” (the option—or liberty—without any granting of any ownership).  Note: I get a blue, zigzagged line under this version—anyway…

3.       Mothers Day = When written this way it is saying that this day is a day for mothers—not a day owned my mother or any one else’s mother.

Compare:

I did some reach on "Valentine's Day" and "Valentine's Day cards—with this, I must agree that I would go with the possessiveness of these two phrases.

You see, Valentine's Day is a possessive phrase that originated from Saint Valentine's Day, and therefore any phrase used to describe something related to Valentine's Day should reflect a similar possessive structure. As a result, instead of “Valentines Day” or "Valentines Day cards" or "Valentine cards", the proper spelling is "Valentine's Day cards.