Source : Webster's Revised Unabridged Dictionary (1913)

Porbeagle \Por"bea`gle\, n. (Zo["o]l.)
   A species of shark ({Lamna cornubica}), about eight feet
   long, having a pointed nose and a crescent-shaped tail; --
   called also {mackerel shark}. [Written {also probeagle}.]

Source : WordNet®

porbeagle
     n : voracious pointed-nose shark of northern Atlantic and
         Pacific [syn: {Lamna nasus}]