: a small book or calendar in which one writes planned or scheduled dates, appointments, etc.
Open my datebook to any day of the week and it's the same story: My daughter is running in a cross-country meet and my younger son is playing baseball. Joyce Maynard
also: a place on a computer or other device for entering similar information
… pull out your calendars or your digital datebook and mark Aug. 20 on your calendar because the MuckFest 5k is coming to town. Rachel Wittrock
(NAmE) ➡ see also diaryVERB + DATEBOOK | PREPOSITIONVERB + DATEBOOK➤note sth down in, put sth (down) in, write sth (down) in在記事本中記下某事◇I wrote it down in my datebook so I wouldn't forget.我把此事記在記事本上,這樣就不會忘記了。PREPOSITION➤in a/your datebook在記事本上