Source : Webster's Revised Unabridged Dictionary (1913)

Natatorium \Na`ta*to"rium\, n. [L.]
   A swimming bath.

Source : WordNet®

natatorium
     n : pool that provides a facility for swimming; "`swimming bath'
         is a British term" [syn: {swimming pool}, {swimming bath}]
     [also: {natatoria} (pl)]