In Rail Terminology:
A fishplate, splice bar or joint bar is a metal bar that is bolted to the ends of two rails to join them together in a track. The name is derived from fish, a wooden bar with a curved profile used to strengthen a ship’s mast. The top and bottom edges are tapered inwards so the device wedges itself between the top and bottom of the rail when it is bolted into place. In rail transport modelling, a fishplate is often a small copper or nickel silver plate that slips onto both rails to provide the functions of maintaining alignment and electrical continuity.
In Greek Culture:
A fish plate is a Greek pottery vessel used by western, Hellenistic Greeks during the Fourth Century B.C. Although invented in Fifth-Century B.C. Athens, most of the corpus of surviving fish plates originate in South Italy, where Fourth-Century B.C. Greek settlers, called “Italiotes,” manufactured them.
The name “fish plate” comes from the usual decoration of these objects which includes various fish and other marine creatures. Fishes depicted include bream, perch, torpedo fish, tuna, flying fish, puffer fish, scorpion fish, squid, cuttlefish, octopus, scallop, clam, dentalia, murex, sea snail, shrimp, crab, dolphin, hippocamp, etc