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]