ISO 31 (Quantities and units, International Organization for Standardization, 1992) is a superseded international standard concerning physical quantities, units of measurement, their interrrelationships and their presentation. It was revised and replaced by ISO/IEC 80000.
The standard comes in 14 parts:
A second international standard on quantities and units was IEC 60027. The ISO 31 and IEC 60027 Standards were revised by the two standardization organizations in collaboration (, ) to integrate both standards into a joint standard ISO/IEC 80000 - Quantities and Units in which the quantities and equations used with SI are to be referred as the International System of Quantities (ISQ). ISO/IEC 80000 supersedes both ISO 31 and part of IEC 60027.
ISO 31-0 introduced several new words into the English language that are direct spelling-calques from the French. Some of these words have been used in scientific literature.
|New phrase||Existing phrase||Technical meaning|
|massic <quantity>||specific <quantity>||a quantity divided by its associated mass|
|volumic <quantity>||[volumic] <quantity> density||a quantity divided by its associated volume|
|areic <quantity>||surface <quantity> density||a quantity divided by its associated area|
|lineic <quantity>||linear <quantity> density||a quantity divided by its associated length|