Didn't attend a university, did you? Either that or you didn't spend much time among peers. Everyone refers to Business Schools, within the University context, as B-School.
Yes, I graduated a major state university with a BS degree.
No, I never once heard anyone refer to B-School before...then again, non of my peers were in the business schools, they were all engineering and chemistry for the most parts.
Most of my peers, believe it or not...were too busy studying, partying or chasing skirt. We didn't sit around much on our free time and discuss "school" or its various departments...geez, who wastes their time doing that?