Perca is the genus of fish referred to as perch or, sometimes, yellow perch, a group of freshwater fish belonging to the family Percidae. Perch, of which there are three species in different geographical areas, lend their name to a large order of vertebrates: the Perciformes, from the Greek perke meaning perch, and the Latin forma meaning shape.
Perch are a popular panfish and are considered to be very good eating; the commercial catch for them has always been in high demand. This has also led to considerable misuse of the term "perch" in the restaurant business in the United States, such as "ocean perch" (Rosefish) and "rock perch" (a small bass). Many restaurants will strive to correctly advertise the offering as "yellow lake perch", or the slightly more ambiguous "lake perch". "White perch", though good eating, is a completely different species of panfish common in New England, and not a member of the order Perciformes.