Marley, I usually think of smart casual as a dressier jeans outfit. So like, dark skinny jeans with a blouse, jacket, scarf, and boots would be a smart casual look. Business casual is one step below business formal to me. Something that would work in a business environment that's not conservative or traditionally oriented (like law). So that would be something like slim trousers, a button-up shirt with a sweater layered over it, and pumps (NO denim). Besides denim, I personally also consider tees or casual knit tops inappropriate for business casual; once they appear, that drops to smart casual in my mind if jeans aren't the bottoms. If they ARE, then it drops to casual. So lastly, casual would be something like a printed tee, flared jeans, a parka, and pointy flats/Cons.
To my eye, MaryK wears a mix of business formal and business casual. Christyg wears business formal. Most of my work outfits are smart casual because I wear a lot of denim.
