- any of a group of elongate elasmobranch, mostly marine fishes, certain species of which are large, voracious, and sometimes dangerous to humans.
- jump the shark, Informal. to begin a decline in quality, popularity, relevance, etc., after reaching a peak: Some TV shows have jumped the shark once a popular cast member left the show.
Origin of shark1
- any of various usually ferocious selachian fishes, typically marine with a long body, two dorsal fins, rows of sharp teeth, and between five and seven gill slits on each side of the head
- a person who preys on or victimizes others, esp by swindling or extortion
- archaic to obtain (something) by cheating or deception
Word Origin and History for jump the shark
1560s, of uncertain origin; apparently the word and the first specimen were brought to London by Capt. John Hawkins's second expedition (landed 1565; see Hakluyt).
There is no proper name for it that I knowe, but that sertayne men of Captayne Haukinses doth call it a 'sharke' [handbill advertising an exhibition of the specimen, 1569]
The meaning "dishonest person who preys on others," though attested only from 1599 (sharker "artful swindler" in this sense is from 1594), may be the original sense, later transferred to the large, voracious marine fish. If so, it is possibly from German Schorck, a variant of Schurke "scoundrel, villain," agent noun of Middle High German schürgen (German schüren) "to poke, stir."
But on another theory, the English word is from a Mayan word, xoc, which might have meant "shark." Northern Europeans seem not to have been familiar with sharks before voyages to the tropics began. A slightly earlier name for it in English was tiburon, via Spanish (where it is attested by 1520s), from the Carib name for the fish.
The English word was applied (or re-applied) to voracious or predatory persons, on the image of the fish, from 1707 (originally of pick-pockets); loan shark is attested from 1905. Sharkskin (1851) was used for binding books, etc. As the name of a type of fabric held to resemble it, it is recorded from 1932.
There is the ordinary Brown Shark, or sea attorney, so called by sailors; a grasping, rapacious varlet, that in spite of the hard knocks received from it, often snapped viciously at our steering oar. [Herman Melville, "Mardi"]