summation in WordNet English dictionary

1. the arithmetic operation of summing; calculating the sum of two or more numbers
   "the summation of four and three gives seven"; "four plus three equals seven"
   summation  addition  plus 
   
2. a concluding summary (as in presenting a case before a law court)
   summation  summing up  rundown 
   
3. the final aggregate
   "the sum of all our troubles did not equal the misery they suffered"
   sum  summation  sum total 
   
4. (physiology) the process whereby multiple stimuli can produce a response (in a muscle or nerve or other part) that one stimulus alone does not produce
   summation