reckoner vs vade mecum

reckoner and vade mecum both are nouns.

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

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

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

Other hypernyms of reckoner include enchiridion, handbook.

reckoner (noun)	vade mecum (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)