Girl is the name of the female player who, as of Episode 81 - The Live Show, gets to play two characters!
Actually a goof the listeners of the Greetings Adventurers podcast came up with, which revolved around the idea that Jennifer Cheek and Nika Howard are, in fact, the same person, sometimes using different voices, depending on who you ask. First brought into the podcast in Episode 86 - The Council of Eight.