In stationery, a diary (UK and Commonwealth English), datebook, daybook, appointment book, planner or agenda (American English) is a small book containing a main diary section with a space for each day of the year with room for notes, a calendar. Usually, various pages at the beginning and end contained various pieces of reference information, which may include maps and telephone codes, and pages for a short address book at the end. Most diaries are pre-printed for a specific year on the cover. With each day's space, they were able to be printed with the day of the week. However, diaries that can be used for any year are also produced. Page-marker ribbons are commonly included. The US Customs official definition of a diary is: "A book prepared for keeping a daily record, or having spaces with printed dates for daily memoranda and jottings; also applied to calendars containing daily memoranda on matters of importance to people generally, or to members of a particular profession, occupation, or pursuit".
The main different sizes produced are the small pocket diary and larger desk diary, both of which come in many different sizes. Any size may be referred to as an appointment diary, especially larger diaries with pre-printed lines for each period in the day, as in the picture above. A large variety of layout formats are sold, including:
