The definition of a diary is a datebook or journal where you record events, emotions, thoughts or feelings.
(noun)See diary in Webster's New World College Dictionary
noun pl. diaries
Origin: L diarium, daily allowance (of food or pay); hence, record of this < dies, day: see deity
See diary in American Heritage Dictionary 4
noun pl. di·a·ries
Origin:
Origin: Latin diārium, daily allowance, daily journal
Origin: , from diēs, day; see dyeu- in Indo-European roots
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