Halibut

from WordNet (r) 3.0 (2006)

halibut
    n 1: lean flesh of very large flatfish of Atlantic or Pacific
    2: marine food fish of the northern Atlantic or northern
       Pacific; the largest flatfish and one of the largest teleost
       fishes [syn: {halibut}, {holibut}]

from The Collaborative International Dictionary of English v.0.48

Halibut \Hal"i*but\ (h[o^]l"[i^]*b[u^]t; 277), n. [OE. hali holy
   + but, butte, flounder; akin to D. bot, G. butte; cf. D.
   heilbot, G. heilbutt. So named as being eaten on holidays.
   See {Holy}, {Holiday}.] (Zool.)
   A large, northern, marine flatfish ({Hippoglossus vulgaris}),
   of the family {Pleuronectid[ae]}. It often grows very large,
   weighing more than three hundred pounds. It is an important
   food fish. [Written also {holibut}.]
   [1913 Webster]