Definition of "Margo"

"I like names that end with an a, don't you? Or other vowels? Most often it seems to be an a. But wait: Margo's name ends with an o, for mercy's sake! Barnaby's mother. Or it used to be o. Then she met Barnaby's father and added a t." Sophia looked at me. I told her, "Mom thought Margot with a t was higher class."

1998 Anne Tyler, A Patchwork Planet, A.A.Knopf Inc., page 3