reckoning vs idea

reckoning and idea both are nouns.

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

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

reckoning (noun)	idea (noun)
the act of counting; reciting numbers in ascending order	the content of cognition; the main thing you are thinking about
problem solving that involves numbers or quantities	your intention; what you intend to do
a bill for an amount due	an approximate calculation of quantity or degree or worth
	a personal view
	(music) melodic subject of a musical composition