Wiktionary
appointment diary
n. a small personal notebook in which one makes a note of future planned events, engagements, appointments, etc., so as not to forget them.
Usage examples of "appointment diary".
But once his secretary enters it in the appointment diary, it will be more difficult to deny.
We should be able to check his story out against Griegs appointment diary, Devray said.
She understands things like filing, and keeping an appointment diary, and paying bills on time.