reckoning vs estimation

reckoning and estimation both are nouns.

Word	Noun	Adjective	Verb	Adverb
reckoning	Yes	No	No	No
estimation	Yes	No	No	No

As nouns, estimation is a hyponym of reckoning; that is, estimation is a word with a more specific, narrower meaning than reckoning:

reckoning (noun)	estimation (noun)
the act of counting; reciting numbers in ascending order	a judgment of the qualities of something or somebody
problem solving that involves numbers or quantities	an approximate calculation of quantity or degree or worth
a bill for an amount due	the respect with which a person is held
	a document appraising the value of something (as for insurance or taxation)