The term 'BIG-EYED FISH' can be summarized by the crossword solution SCAD, which is a four letter word. SCAD stands for the family of fish known as Scombridae, which are commonly referred to as mackerels. These fish are characterized by their large eyes and streamlined bodies, making them well-suited for fast swimming. They are found in tropical and temperate waters around the world, and are an important food source for many cultures.