Abbreviation for a valued significant other often referred to as the "ball and chain"
Dude 1: "Missed you at bowling last
night, brah. What gives?"
Dude 2: "My BNC was on some rant
that I never spend time with her so I stayed
Dude 1: "BNC's are like that sometime! They have a way of dealing you in!"
Dude 2: "Tell me about it!"