Well I can't speak for Angie, but when I think of business formal, I think of suits (whether broken up or matching, skirts or pants), minimal jewelry and makeup, closed-toe shoes, hose, and generally very conservative work attire. Business casual involves smart crisp shirts or layered tops, pants and skirts, but not necessarily suits or jackets. Brighter colors are more acceptable for BC than BF. Smart casual is a kind of running-around-on-the-weekend look with jeans, ballet flats or fashion sneakers, denim skirts and funky jewelry, etc. This is opposed to dumb casual, which is sweatpants and a pair of Ugg boots
However, I went to work today in Converse sneakers, medium wash slim bootcut jeans, a chunky shawl collar cardigan, and a red tank--the point being that for me, what most people consider "business casual" is formal attire. And before anyone gasps, everyone of all positions in my department dresses that way. It's pretty laid back. So I guess it does depend on your job to a degree.