I don't believe that there is any actual noun in English usage with that spelling. Graw is a very common misspelling for the word "grow" however. Perhaps taking a look at the context of where you saw the word would show that is what the word should be.
Graws
The correct spelling is "Mardi Gras", also know as "Lundi Gras" and "Fat Tuesday". "Founded" by France and popularized in New Orleans, Louisiana