in a reasonable establishment: I never fully grasp the diff, only had inklings
Don't be embarrassed, I hear commentary all the time on espn about how professional sport players sometimes forget the fundamentals of their own game.
1) Hand Roll - fish wrapped by rice - fits in palm of hand (cone-shape)
2) Roll - fish surrounded by circumference of rice - cut into 6 cylinders
3) Sushi - sliver of fish on top, rice bottom (1/2 fish of Roll, same amt rice, ~$3)
4) Sashimi - fish in rectangular prizm, no rice