horse mackerel vs jack mackerel

horse mackerel and jack mackerel both are nouns.

Word	Noun	Adjective	Verb	Adverb
horse mackerel	Yes	No	No	No
jack mackerel	Yes	No	No	No

As nouns, horse mackerel and jack mackerel are synonyms defined as:

Other synonyms of horse mackerel include saurel, Spanish mackerel, Trachurus symmetricus.

horse mackerel (noun)	jack mackerel (noun)
a California food fish	a California food fish
large elongated compressed food fish of the Atlantic waters of Europe
largest tuna; to 1500 pounds; of mostly temperate seas: feed in polar regions but breed in tropics