BS ISO/IEC 14651:2016+A1:2017 defines the following.

A reference comparison method. This method is applicable to two character strings to determine their collating order in a sorted list. The method can be applied to strings containing characters from the full repertoire of ISO/IEC 10646. This method is also applicable to subsets of that repertoire, such as those of the different ISO/IEC 8-bit standard character sets, or any other character set, standardized or not, to produce ordering results valid (after tailoring) for a given set of languages for each script. This method uses collation tables derived either from the Common Template Table defined in this International Standard or from one of its tailorings. This method provides a reference format. The format is described using the Backus-Naur Form (BNF). This format is used to describe the Common Template Table. The format is used normatively within this International Standard.

Cross References:
ISO/IEC 10646:2014/Amd 2:2016
ISO/IEC 10646:2014
IEC 8859-9
DS 377:1980
IEC 8859-3
IEC 8859-14
IEC 8859-1
IEC 8859-10
IEC 8859-15
IEC 8859-4
IEC 8859-8
IEC 8859-13
IEC 8859-2
IEC 8859-5
IEC 8859-6
IEC 646
CSA Z243.4.1:1998
IEC 8859-7
IEC 2022
Unicode Technical Report No. 15
Unicode Technical Report No. 10
IEC 6937
IEC 9945-3
TR 14652:2004
CSA Z243.230:1998


Incorporates the following:
Amendment, May 2018