Other forms: prawns; prawning
A prawn is a crustacean that resembles a big shrimp, with long antennae and a shell. When you see prawns on a menu, just imagine large, juicy shrimp.
The words shrimp and prawn are used interchangeably so often that the difference between them has blurred. In many English-speaking parts of the world, prawn is the more common term, while North Americans reserve that word for freshwater shrimp (as opposed to ocean shrimp). Prawn is a common name, rather than a scientific one — if you want to sound knowledgable, you can call this animal a decapod crustacean of the sub-order Dendrobranchiata.