tuna

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Any of various often large scombroid marine food and game fishes of the genus Thunnus and related genera, many of which, including T. thynnus and the albacore, are commercially important sources of canned fish. Also called tunny.
2. n. Any of several related fishes, such as the bonito.
3. n. The edible flesh of tuna, often canned or processed. Also called tuna fish.
4. n. Any of several flat-jointed tropical American cacti of the genus Opuntia, which includes the prickly pears, especially O. tuna of Jamaica, having yellow flowers and edible red fruit.
5. n. The edible fruit of any of these cacti. Also called cactus pear.

Century Dictionary and Cyclopedia

1. n. The common eel of New Zealand, Anguilla aucklandii.
2. n. A fish. See Thynnus, Sarda, Orcynus, and tunny.
3. n. A species of prickly-pear, Opuntia Tuna, or its fruit. It grows erect, sometimes 20 feet high, is spiny, and is much used for hedges in southern Europe. Its fruit, which is barrel-shaped and 2 or 3 inches long, is much eaten, fresh and dried. It is one of the foremost cochineal-plants, and is said to be the only species used for this production in the Canaries.

Wiktionary

1. n. Any of several species of fish, of the genus Thunnus, in the family Scombridae.
2. n. The edible flesh of the tuna.
3. n. A type of cactus native to Mexico in the genus Opuntia.
4. n. The fruit of the cactus.

GNU Webster's 1913

1. n. (Bot.) The Opuntia Tuna. See Prickly pear, under prickly.
2. n. (Zoöl.) Any one of several species of large oceanic fishes belonging to the mackerel family Scombridae, especially the bluefin tuna (Thunnus thynnus, formerly Orcynus thynnus or Albacora thynnus), called also the common tunny or great tunny, a native of the Mediterranean Sea and of temperate parts of the Atlantic Ocean. It sometimes weighs a thousand pounds or more, and is caught commercially in large quantity for use as food; -- also called, especially in Britain, tunny. It is also one of the favorite fishes used by the Japanese in preparing sushi. On the American coast, especially in New England, it is sometimes called the horse mackerel. Another well-known species is the yellowfin tuna (Thunnus albacares) of warm seas. the See Illust. of Horse mackerel, under horse.
3. n. The bonito, 2.
4. n. the meat of the tuna, used as food; -- also called tuna fish.

WordNet 3.0

1. n. important warm-water fatty fish of the genus Thunnus of the family Scombridae; usually served as steaks
2. n. any very large marine food and game fish of the genus Thunnus; related to mackerel; chiefly of warm waters
3. n. tropical American prickly pear of Jamaica
4. n. New Zealand eel