General English

Information & Library Science

  • noun a detailed daily record of the events in a person’s life written in a book
  • noun a small book with dates and blank spaces used to record appointments


  • noun a book in which you can write notes or appointments for each day of the week and record events which have taken place

Origin & History of “diary”

like its semantic cousin journal, a diary is literally a ‘daily’ record. It comes from Latin diarium, a derivative of diēs ‘day’. Originally in classical Latin the word meant ‘daily allowance of food or pay’, and only subsequently came to be applied to a ‘record of daily events’. From the 17th to the 19th century English also had an adjective diary, from Latin diarius, meaning ‘lasting for one day’.