Source : Webster's Revised Unabridged Dictionary (1913)

Vichy water \Vi"chy wa`ter\
   A mineral water found at Vichy, France. It is essentially an
   effervescent solution of sodium, calcium, and magnetism
   carbonates, with sodium and potassium chlorides; also, by
   extension, any artificial or natural water resembling in
   composition the Vichy water proper. Called also,
   colloquially, Vichy.

Source : WordNet®

Vichy water
     n : sparkling mineral water from springs at Vichy, France or
         water similar to it