di·a·ry 
(dīə-rē)
(dīə-rē)n. pl. di·a·ries
1.
a. A usually daily written record of personal experiences and observations; a journal.
b. A daily record of events or measurable phenomena, usually kept to track patterns over time: kept a diary of blood sugar levels.
2. A book or computer file used for keeping such a record.
[Latin diārium, daily allowance, daily journal, from diēs, day; see dyeu- in the Appendix of Indo-European roots.]