Definition of sea-lily:
(n) :
The ocean; the continuous body of salt water covering a majority of the Earth's surface.
(n) :
A large body of salt water.
(n) :
A body of salt water smaller than an ocean, generally forming part of, or connecting with, an ocean or a larger sea.
(n) :
A lake, especially if large or if salty or brackish.
(n) :
The swell of the sea, especially when high or rough.
(n) :
A single wave; billow.