Menenza is definitely a spanish last name. What it means I have no clue, but it does not surprise me that a last name is used as a first name in an english speaking country. I am from Uruguay and I do not remember that happening much. Obviously your grandma must have liked the name and wanted to be original. My father used to tell this story from when he was a kid, and this boy's parents had named him Watercloset, can you imagine? Here in New Bern, there is a guy named Stewart Smith, I always thought Stewart was a last name only. On TV the other day, they had a report from this town in Colombia, I beleive, where people have the strangest names like helicopter, tree, just crazy names, all because it is the tradition in that area to name your kids something related to things or events surrounding the day of your birth. Also, they were talking on the radio, the other day, that people here, in the States, are naming their kids Lexus, Xerox, Bologna, Bentley, etc. So, you see, people have been naming their kids whatever they like. I did try to find the meaning on the web, but was not that lucky.