book vs journal

book and journal both are nouns.

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

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

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

Other hyponyms of book include cost ledger, general ledger, subsidiary ledger, daybook.

book (noun)	journal (noun)
physical objects consisting of a number of pages bound together	the part of the axle contained by a bearing
a number of sheets (ticket or stamps etc.) bound together on one edge	a record book as a physical object
a written work or composition that has been published (printed on pages bound together)	a periodical dedicated to a particular subject
a written version of a play or other dramatic composition; used in preparing for a performance	a daily written record of (usually personal) experiences and observations
a compilation of the known facts regarding something or someone	a ledger in which transactions have been recorded as they occurred
a major division of a long written composition
a collection of rules or prescribed standards on the basis of which decisions are made
a collection of playing cards satisfying the rules of a card game
a record in which commercial accounts are recorded

book (verb)	journal (verb)
engage for a performance
record a charge in a police register
arrange for and reserve (something for someone else) in advance
register in a hotel booker