n 1  :  something stored or kept available for future use or need <oxygen >  - see CARDIAC RESERVE   2  :  the capacity of a solution to neutralize alkali or acid when its reaction is shifted from one hydrogen-ion concentration to another : esp  :  the capacity of blood or bacteriological media to react with acid or alkali within predetermined and usu. physiological limits of hydrogen-ion concentration - compare BUFFER BUFFER SOLUTION 
, adj :  constituting or having the form or function of a reserve <a supply>  < strength>  .
 
 
 
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