chick-mate

1. Brit/Aus colloq. A female friend, a gal pal, etc, usually fairly attractive, that is part of your otherwise male 'crew' or mates, but generates no sexual interest or feelings from either you or your other male friends of that group as they seem to be just accepted as one of the guys.

2. A girl you are friends with but, due to not being able to take the relationship further, reaffirm to yourself as only a friend and/or even outwardly advise as such to people who inquire as your relationship.

John: "Wow, that chick standing over there having a laugh with your mates is pretty hot. I guess you'd like to do her, eh?"
Jack: "Nah, she's a chick-mate. It'd be, y'know, like, doing one of the guys... yech!"