vade mecum vs reckoner

vade mecum and reckoner both are nouns.

Word	Noun	Adjective	Verb	Adverb
vade mecum	Yes	No	No	No
reckoner	Yes	No	No	No

As nouns, reckoner is a hyponym of vade mecum; that is, reckoner is a word with a more specific, narrower meaning than vade mecum:

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

Other hyponyms of vade mecum include manual, bible, guide, guidebook, ready reckoner.

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