Define Girlfriend

The other day Biff walks in to this party wearing a shirt that said "define girlfriend". So here goes...

The term girlfriend can have several meanings:
*When used by a heterosexual girl or woman, the term "girlfriend" usually denotes a close female friend and has no sexual or romantic connotation. Although long popular in the United States, this usage was unknown in the United Kingdom until relatively recently, but is now becoming more common. Sometimes, the phrase girl friend (with a space) or friend girl is used to avoid confusion with the romantic meaning.
*The female partner in a non-marital romantic relationship with a male. In this sense the term is generally used to describe a male's courting partner or "lover" and is used by all age groups. For example, "He took his girlfriend out to dinner and a movie."
*When used by a lesbian or bisexual woman, the term "girlfriend" is almost always used to refer to a female that is involved in a romantic and/or sexual relationship with that person; in this usage, it is synonymous with "partner".
*When used by a gay man, the term may refer to either the first sense listed above, or in a camp way, to any person he may be addressing.

That should do it.
Thanks!