Prawns, shrimps and dried shrimps
Prawns and shrimps are not only a seafood, but fresh water creatures as well. The difference is in size. Prawns are the larger ones.
The names are usually interchangable, but recently prawn is used for the fresh water ones and shrimp for the marine ones. They are used in cuisine all over the world.
You can get them in many levels of freshness. In areas close to the sea in Asia, they usually buy and cook them still alive. You can get them frozen, with shells of without. If they are grey in color, it means they were not cooked yet. The pink ones are precooked already. Dried shrimps are a very common ingredients in Thai cuisine, e.g. in green papaya salad.
If you see a prawn on your plate, which seems like cut in the middle, it means it was gutted. In Thailand they do it pretty often, like for instance in this prawn yellow curry.