Compendium of Analytical Nomenclature
The Compendium of Analytical Nomenclature is an IUPAC nomenclature book published by the International Union of Pure and Applied Chemistry (IUPAC) containing internationally accepted definitions for terms in analytical chemistry. It has traditionally been published in an orange cover, hence its informal name, the Orange Book.
Source: Wikipedia — Compendium of Analytical Nomenclature (CC BY-SA 4.0)