blotter vs day book

blotter and day book both are nouns.

Word	Noun	Adjective	Verb	Adverb
blotter	Yes	No	No	No
day book	Yes	No	No	No

As nouns, blotter and day book are synonyms defined as:

blotter and day book: the daily written record of events (as arrests) in a police station

Other synonyms of blotter include charge sheet, police blotter, rap sheet.

blotter (noun)	day book (noun)
the daily written record of events (as arrests) in a police station	the daily written record of events (as arrests) in a police station
absorbent paper used to dry ink