subtracter vs reckoner

subtracter and reckoner both are nouns.

Word	Noun	Adjective	Verb	Adverb
subtracter	Yes	No	No	No
reckoner	Yes	No	No	No

As nouns, reckoner is a hypernym of subtracter; that is, reckoner is a word with a broader meaning than subtracter:

Other hypernyms of subtracter include calculator, computer, estimator, figurer.

subtracter (noun)	reckoner (noun)
a machine that subtracts numbers	a handbook of tables used to facilitate computation
a person who subtracts numbers	an expert at calculation (or at operating calculating machines)