Today I learned: Sometimes "lobster" is not lobster, and shrimp is not prawn

I used to think that shrimp is just small prawns. Turns out I was wrong. 

Shrimp is under the pleocyemata sub-order, while prawns are in the Dendrobranchiata sub-order. 

Too technical? Shrimp are sea creatures and are generally small and curved. Prawns are usually fresh-water creatures and usually larger and straight. 

At least in AMERICAN usage. Folks elsewhere may refer to them differently. 

So just for fun I looked up langoustines, which is something ELSE entirely. Sometimes called Norway lobster, it's basically a small lobster that grows up to 25 cm long, but typically about 20 cm long, which isn't that big, and has a narrow body. Compare that to what's usually known in the US, the "Maine lobster". 

There's also "squat lobster", which is actually a type of crab. But their meat looks about the same, so much so, that Red Lobster was once caught substituting squat lobster meat for real lobster meat. And this was apparently common practice many years ago.