Source : Webster's Revised Unabridged Dictionary (1913)

Shark \Shark\, n. [Of uncertain origin; perhaps through OF. fr.
   carcharus a kind of dogfish, Gr. karchari`as, so called from
   its sharp teeth, fr. ka`rcharos having sharp or jagged teeth;
   or perhaps named from its rapacity (cf. {Shark}, v. t. & i.);
   cf. Corn. scarceas.]
   1. (Zo["o]l.) Any one of numerous species of elasmobranch
      fishes of the order Plagiostomi, found in all seas.

   Note: Some sharks, as the basking shark and the whale shark,
         grow to an enormous size, the former becoming forty
         feet or more, and the latter sixty feet or more, in
         length. Most of them are harmless to man, but some are
         exceedingly voracious. The man-eating sharks mostly
         belong to the genera {Carcharhinus}, {Carcharodon}, and
         related genera. They have several rows of large sharp
         teeth with serrated edges, as the great white shark
         ({Carcharodon carcharias, or Rondeleti}) of tropical
         seas, and the great blue shark ({Carcharhinus glaucus})
         of all tropical and temperate seas. The former
         sometimes becomes thirty-six feet long, and is the most
         voracious and dangerous species known. The rare
         man-eating shark of the United States coast
         ({Charcarodon Atwoodi}) is thought by some to be a
         variety, or the young, of {C. carcharias}. The dusky
         shark ({Carcharhinus obscurus}), and the smaller blue
         shark ({C. caudatus}), both common species on the coast
         of the United States, are of moderate size and not
         dangerous. They feed on shellfish and bottom fishes.

   2. A rapacious, artful person; a sharper. [Colloq.]

   3. Trickery; fraud; petty rapine; as, to live upon the shark.
      [Obs.] --South.

   {Baskin shark}, {Liver shark}, {Nurse shark}, {Oil shark},
   {Sand shark}, {Tiger shark}, etc. See under {Basking},
      {Liver}, etc. See also {Dogfish}, {Houndfish},
      {Notidanian}, and {Tope}.

   {Gray shark}, the sand shark.

   {Hammer-headed shark}. See {Hammerhead}.

   {Port Jackson shark}. See {Cestraciont}.

   {Shark barrow}, the eggcase of a shark; a sea purse.

   {Shark ray}. Same as {Angel fish}
      (a), under {Angel}.

   {Thrasher} shark, or {Thresher shark}, a large, voracious
      shark. See {Thrasher}.

   {Whale shark}, a huge harmless shark ({Rhinodon typicus}) of
      the Indian Ocean. It becomes sixty feet or more in length,
      but has very small teeth.

Tiger \Ti"ger\, n. [OE. tigre, F. tigre, L. tigris, Gr. ti`gris;
   probably of Persian origin; cf. Zend tighra pointed, tighri
   an arrow, Per. t[=i]r; perhaps akin to E. stick, v.t.; --
   probably so named from its quickness.]
   1. A very large and powerful carnivore ({Felis tigris})
      native of Southern Asia and the East Indies. Its back and
      sides are tawny or rufous yellow, transversely striped
      with black, the tail is ringed with black, the throat and
      belly are nearly white. When full grown, it equals or
      exceeds the lion in size and strength. Called also {royal
      tiger}, and {Bengal tiger}.

   2. Fig.: A ferocious, bloodthirsty person.

            As for heinous tiger, Tamora.         --Shak.

   3. A servant in livery, who rides with his master or
      mistress. --Dickens.

   4. A kind of growl or screech, after cheering; as, three
      cheers and a tiger. [Colloq. U. S.]

   5. A pneumatic box or pan used in refining sugar.

   {American tiger}. (Zo["o]l.)
      (a) The puma.
      (b) The jaguar.

   {Clouded tiger} (Zo["o]l.), a handsome striped and spotted
      carnivore ({Felis macrocelis} or {F. marmorata}) native of
      the East Indies and Southern Asia. Its body is about three
      and a half feet long, and its tail about three feet long.
      Its ground color is brownish gray, and the dark markings
      are irregular stripes, spots, and rings, but there are
      always two dark bands on the face, one extending back from
      the eye, and one from the angle of the mouth. Called also
      {tortoise-shell tiger}.

   {Mexican tiger} (Zo["o]l.), the jaguar.

   {Tiger beetle} (Zo["o]l.), any one of numerous species of
      active carnivorous beetles of the family {Cicindelid[ae]}.
      They usually inhabit dry or sandy places, and fly rapidly.
      

   {Tiger bittern}. (Zo["o]l.) See {Sun bittern}, under {Sun}.
      

   {Tiger cat} (Zo["o]l.), any one of several species of wild
      cats of moderate size with dark transverse bars or stripes
      somewhat resembling those of the tiger.

   {Tiger flower} (Bot.), an iridaceous plant of the genus
      {Tigridia} (as {T. conchiflora}, {T. grandiflora}, etc.)
      having showy flowers, spotted or streaked somewhat like
      the skin of a tiger.

   {Tiger grass} (Bot.), a low East Indian fan palm
      ({Cham[ae]rops Ritchieana}). It is used in many ways by
      the natives. --J. Smith (Dict. Econ. Plants).

   {Tiger lily}. (Bot.) See under {Lily}.

   {Tiger moth} (Zo["o]l.), any one of numerous species of moths
      of the family {Arctiad[ae]} which are striped or barred
      with black and white or with other conspicuous colors. The
      larv[ae] are called {woolly bears}.

   {Tiger shark} (Zo["o]l.), a voracious shark ({Galeocerdo
      maculatus or tigrinus}) more or less barred or spotted
      with yellow. It is found in both the Atlantic and Indian
      Ocean. Called also {zebra shark}.

   {Tiger shell} (Zo["o]l.), a large and conspicuously spotted
      cowrie ({Cypr[ae]a tigris}); -- so called from its fancied
      resemblance to a tiger in color and markings. Called also
      {tiger cowrie}.

   {Tiger wolf} (Zo["o]l.), the spotted hyena ({Hy[ae]na
      crocuta}).

   {Tiger wood}, the variegated heartwood of a tree
      ({Mach[ae]rium Schomburgkii}) found in Guiana.

Source : WordNet®

tiger shark
     n : large dangerous warm-water shark with striped or spotted
         body [syn: {Galeocerdo cuvieri}]