Vichy water (3)
I believe the answer is:
eau
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">vichy water</span>' is the definition.<br/ ><span class="explanation-format__explanation">('water' in French - eg in the French town Vichy)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for eau that I've seen before include "Water in France" , "French water, may be Cologne" , "Perrier water" , "French water from chateaux" , "French water - de Cologne?" .)