approximation vs reckoning

approximation and reckoning both are nouns.

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

As nouns, reckoning is a hypernym of approximation; that is, reckoning is a word with a broader meaning than approximation:

Other hypernyms of approximation include calculation, computation, figuring.

approximation (noun)	reckoning (noun)
the act of bringing near or bringing together especially the cut edges of tissue	the act of counting; reciting numbers in ascending order
the quality of coming near to identity (especially close in quantity)	problem solving that involves numbers or quantities
an approximate calculation of quantity or degree or worth	a bill for an amount due
an imprecise or incomplete account