journal vs daybook

journal and daybook both are nouns.

Word	Noun	Adjective	Verb	Adverb
journal	Yes	No	No	No
daybook	Yes	No	No	No

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

Other hyponyms of journal include ledger, diary.

As nouns, journal and daybook are synonyms defined as:

journal and daybook: a ledger in which transactions have been recorded as they occurred

journal (noun)	daybook (noun)
the part of the axle contained by a bearing	an accounting journal as a physical object
a record book as a physical object	a ledger in which transactions have been recorded as they occurred
a periodical dedicated to a particular subject
a daily written record of (usually personal) experiences and observations
a ledger in which transactions have been recorded as they occurred