From Longman Dictionary of Contemporary Englishprawnprawn /prɔːn $ prɒːn/ ●○○ noun [countable] especially British English 
HBFDFa small pink shellfish that can be eaten SYN shrimp American English a prawn sandwich prawn cocktail (=a small dish of prawns in a sauce with some salad)
HBFDFa small pink shellfish that can be eaten SYN shrimp American English a prawn sandwich prawn cocktail (=a small dish of prawns in a sauce with some salad)Examples from the Corpus
prawn• Add prawns for 7 to 10 minutes.• Much nicer and far more refreshing than the bland oiliness of avocado and prawns, a combination which still baffles me.• Specialities include deep fried shredded beef, duck, prawn dishes and hand-made noodles.• The Bichirs take like and frozen Tubifex, frozen prawn, and catfish pellets.• Include prawns for a special treat or add chicken or ham for a really substantial meal.• Islay Prawn Delight - prawns blended with mayonnaise and malt whisky. 6.• The tuna tartare with chopped avocado, the clam chowder with smoked bacon and the giant Louisiana prawns were all a hit.• Though prawns are low in calories, they are then smothered in a dressing loaded with them. 