A marlin is a fish from the family Istiophoridae (includes about 10 species). It has an elongated body, a spear-like snout or bill, and a long, rigid dorsal fin which extends forward to form a crest. Its common name is thought to derive from its resemblance to a sailor's marlinspike. Even more so than their close relatives, the scombrids, marlins are fast swimmers, reaching speeds of about .

Marlín is a village and municipality located in the province of Ávila, part of the autonomous community of Castile-Leon, Spain. It has approximately 38 inhabitants.

The Marine Life Information Network (MarLIN) is an information system for marine biodiversity  for Great Britain and Ireland.