reckoner vs enchiridion

reckoner and enchiridion both are nouns.

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

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

reckoner: a handbook of tables used to facilitate computation
enchiridion: a concise reference book providing specific information about a subject or location

Other hypernyms of reckoner include handbook, vade mecum.

reckoner (noun)	enchiridion (noun)
a handbook of tables used to facilitate computation	a concise reference book providing specific information about a subject or location
an expert at calculation (or at operating calculating machines)