Remember when there was only one "best?" In fact, any word ending in –est meant "alone at the top."
[Hmmm, what's a "best seller" then? Shouldn't there be only one? But many of us use the term, even if we topped the chart of a local bookstore in Burlington, Kansas, one week in 2003. But maybe that's another blog topic.]
When I was a kid, the label "best friend" was very clearly defined. You could have only one, or one at a time anyway. There was constant checking, like "How come you gave Ruthie B. half your sandwich? You wanna be best friends with her, ok, just let me know and I'll be best friends with Annie M."
Here's one of my best friends, Geraldine I., on the right. She died the same month that I was creating a new protagonist for my miniature mysteries. Naming Geraldine Porter after her was a way of keeping my friend with me.
The first fictional best friend I created was Rose Galigani, a classy mother of three and a funeral director. I gave her to my first protagonist Gloria Lamerino in the periodic table mysteries.
When she appeared in print, one of my friends, Natalie W., from grade school called me. She, too, has three children, and she was thrilled to be the basis for Rose. Never mind that Rose wears a size 2 and Natalie shops in the fuller figure department.
Another high school friend, Lena P., called to thank me for modeling Rose after her. She has a daughter named Mary, just as Rose does. Never mind that there are no other similarities.
Three other friends claimed to have inspired Rose, one because Rose has red highlights, another because she has a garden, and the third because Rose has traveled to Italy.
I suppose they all were my inspiration, each in her own way. They were all my best friends at one time. Maybe it's cumulative. Once a best friend, always a best friend; there's simply a longer list of BFs as we get older. Thus, BFF.