Definition
A book which lists record-breaking achievements.
Origins
From record + book.
How People Actually Use It
The most commonly stolen book from public libraries. Also a widely renown source of the biggest, most expensive and most weird things on the planet. A throughouhly interesting read.
"Person 1: "Hey man, check out what I just scored from the library!" Person 2: "Dude, it's just the Guiness Book of Records. Save yourself the late fees and go buy it for $10""
Source: Urban Dictionary