Last night my friend and I had a discussion about the differences (if any) between shrimp and prawns. (After many beers our conversations sometimes become slightly arcane). Anyway, he believed there is a size difference - prawns are larger. I thought the name discrepancy was due to a difference in British and American naming conventions.
For example, we have "lines" and "train cars", they have "queues" and "railway carriages". On many trips to Britain and Australia I have always seen "prawns" on restaurant menus, never "shrimp". Here in the States menus usually refer to "shrimp". The exception is a certain type of restaurant which delights in gilding their menus - common green beans morph into glamorous "haricots verts" and shrimp are magically transformed into aristocratic "prawns."
Is there an actual difference or is my cynicism justified?