Sorry about throwing scientific names around, but really it's the only meaningful way of referring to species. There are no standards in common names (though attempts have been made, for instance, for North American fishes and here in Oz for Australian species), and often suppliers will make up names on the spot. Some are also likely to cause confusion. Consider the common name "yellow coris", which usually refers to Halichoeres chyrurus .... so not a Coris at all (a rather different genus of wrasses with small scales). Banana wrasse is another case for possible confusion, as although sometimes it is used for H. chrysurus, it is the name usually given to the much larger (and somewhat nastier)Thalassoma lutescens. I admit that some of the scientific names are a mouthful, but it's the best we have at the moment.
So, you say jack and we say trevally ... let's call the whole thing a carangid.
Tony