Small slender-bodied chiefly marine decapod crustaceans with a long tail and single pair of pincers; many species are edible WordNet 3.0 & Open English WordNet

A shrimp is a crustacean with an elongated body and a primarily swimming mode of locomotion – typically belonging to the Caridea or Dendrobranchiata of the decapod order, although some crustaceans outside of this order are also referred to as "shrimp". Wikipedia

Stalk-eyed swimming crustaceans. Wikipedia Disambiguation

A decapod crustacean of the suborder Dendrobranchiata. OmegaWiki

Any of many swimming, often edible crustaceans, chiefly of the infraorder Caridea or the suborder Dendrobranchiata, with slender legs, long whiskers and a long abdomen. Wiktionary