Definitions of (the) Bluebook
a standardized guide of how to write and provide references to citations in legal documents and journals
The Harvard Bluebook is the standard legal citation form guide for law reviews and federal courts.
a term used in some professions to describe some kind of reference manual commonly used in that profession
Under date of March 7, 1946, the Commission published a report entitled "Public Service Responsibility of Broadcast Licensees", commonly referred to as the "Blue Book".