S: (n) summation ((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)
S: (n) sum, summation, sum total (the final aggregate) "the sum of all our troubles did not equal the misery they suffered"
S: (n) summation, addition, plus (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"