summation vs rundown

summation and rundown both are nouns.

Word	Noun	Adjective	Verb	Adverb
summation	Yes	No	No	No
rundown	Yes	No	No	No

As nouns, summation and rundown are synonyms defined as:

summation and rundown: a concluding summary (as in presenting a case before a law court)

Other synonyms of summation include summing up.

summation (noun)	rundown (noun)
the arithmetic operation of summing; calculating the sum of two or more numbers	a concluding summary (as in presenting a case before a law court)
a concluding summary (as in presenting a case before a law court)
the final aggregate
(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