According to the crustacean taxonomist Tin-Yam Chan, "The terms
shrimp and
prawn have no definite reference to any known taxonomic groups. Although the term
shrimp is sometimes applied to smaller species, while
prawn is more often used for larger forms, there is no clear distinction between both terms and their usage is often confused or even reverse in different countries or regions Writing in 1980,
L. B. Holthuis noted that the terms
prawn and
shrimp were used inconsistently "even within a single region", generalising that larger species fished commercially were generally called
shrimp in the United States, and
prawns in other English-speaking countries, although not without exceptions.