horse mackerel noun 12forms 1 noun12 •Any of several large fishes of many species. •Alectis indica (Indian threadfish) •Atule (certain scads) •Caranx spp. (certain trevallies) •Carangoides spp. (island jacks) •Gnathanodon speciosus (golden trevally) •Megalaspis cordyla (torpedo scad) •Sarda sarda (Atlantic bonito) •Sarda australis (Australian bonito) •Selar crumenophthalmus (bigeye scad) •Naucrates ductor (pilot fish) •Trachurus spp. (jack mackerels). formshorse mackerels