The Collaborative International Dictionary of English v.0.48:

Daybook \Day"book`\ (d[=a]"b[oo^]k`), n.
   A journal of accounts; a primary record book in which are
   recorded the debts and credits, or accounts of the day, in
   their order, and from which they are transferred to the
   journal.
   [1913 Webster]

WordNet (r) 3.0 (2006):

daybook
    n 1: a ledger in which transactions have been recorded as they
         occurred [syn: daybook, journal]
    2: an accounting journal as a physical object; "he bought a new
       daybook" [syn: daybook, ledger]

Moby Thesaurus II by Grady Ward, 1.0:

100 Moby Thesaurus words for "daybook":
   Domesday Book, account book, accounts payable ledger,
   accounts receivable ledger, address book, adversaria, album,
   annals, annual, appointment calendar, appointment schedule,
   balance sheet, bank ledger, bankbook, bimonthly, biweekly,
   blankbook, blotter, books, calendar, card ledger, cashbook,
   catalog, check sheet, chronicle, chronology, classified catalog,
   clock card, commonplace book, cost card, cost ledger, cost sheet,
   court calendar, daily, date slip, datebook, desk calendar, diary,
   diptych, docket, engagement book, ephemeris, factory ledger,
   fortnightly, gazette, inventory, journal, ledger, log, logbook,
   loose-leaf notebook, magazine, memo book, memorandum book,
   memory book, monthly, newsmagazine, notebook, organ, pad, passbook,
   periodical, petty cashbook, pictorial, pocket notebook, pocketbook,
   police blotter, purchase ledger, quarterly, record, record book,
   register, registry, review, sales journal, sales ledger, scrapbook,
   scratch pad, serial, slick magazine, spiral notebook, stock ledger,
   stores ledger, suspense ledger, table, tablet, time book,
   time chart, time scale, time schedule, time sheet, time study,
   timecard, timetable, trade magazine, triptych, weekly, workbook,
   writing tablet, yearbook