Resolution 7 of the 9th CGPM (1948)

Writing and printing of unit symbols and of numbers

Principles

Roman (upright) type, in general lower case, is used for symbols of units; if, however, the symbols are derived from proper names, capital roman type is used. These symbols are not followed by a full stop.

In numbers, the comma (French practice) or the dot (British practice) is used only to separate the integral part of numbers from the decimal part. Numbers may be divided in groups of three in order to facilitate reading; neither dots nor commas are ever inserted in the spaces between groups.

Notes

1. The symbols whose unit names are preceded by dots are those which had already been adopted by a decision of the CIPM.
2. The symbol for the stere, the unit of volume for firewood, shall be "st" and not "s", which had been previously assigned to it by the CIPM.
3. To indicate a temperature interval or difference, rather than a temperature, the word "degree" in full, or the abbreviation "deg" must be used.

DOI : 10.59161/CGPM1948RES7E

NOTE

The CGPM abrogated certain decisions on units and terminology, in particular: micron, degree absolute, and the terms "degree", and "deg", 13th CGPM, 1967 (Resolutions 7 and 3), and the litre; 16th CGPM, 1979 (Resolution 6).