Colloquial term of a usually possessive nature indicating a female with whom one is either emotionally or physically intimate. Usually refers to a wife or girlfriend, although it can be extended to a fuck buddy, or even a platonic relationship, of close enough. This is similar to the informal use of the word "bitch" among girlfriends, but applicable to male usage.
> Clair and I aren't dating, but she's just about the coolest vaginal unit I've met since college, you should totally meet her!