Webster's Revised Unabridged Dictionary · 1913

Halibut

Halibut (hol"i*but; 277) , noun

[Old English hali holy + but, butte, flounder; akin to Dutch bot, German butte; compare Dutch heilbot, German heilbutt. So named as being eaten on holidays. See Holy, Holiday.]

(Zoology) A large, northern, marine flatfish (Hippoglossus vulgaris), of the family Pleuronectidae. It often grows very large, weighing more than three hundred pounds. It is an important food fish.