accumulation in WordNet English dictionary

1. an increase by natural growth or addition
   accretion  accumulation 
   
2. the act of accumulating
   accumulation  accrual  accruement 
   
3. several things grouped together or considered as a whole
   collection  aggregation  accumulation  assemblage 
   
4. (finance) profits that are not paid out as dividends but are added to the capital base of the corporation
   accumulation