International Standards and Conformity Assessment for all electrical, electronic and related technologies
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Drafting IEC publications



Terms and definitions

(The full requirements are described in the ISO/IEC Directives Part 2:2011, 6.3.1 and Annex D.)


This conditional element gives definitions necessary for the understanding of certain terms used in the document.


Introductory text

One of the following introductory sentences shall be used:

  • “For the purposes of this document, the following terms and definitions apply.”
  • “For the purposes of this document, the terms and definitions given in [another publication] and the following apply.”

This introductory text is not a hanging paragraph, as described in the ISO/IEC Directives Part 2:2011, 5.2.4, since the terms and definitions are a list of terminological entries and not a series of subclauses.


Status of terms

Differentiate preferred, admitted and undesired terms and place each term on a separate line (see ISO/IEC Directives Part 2:2011, D.4.2). Do not use parentheses or square brackets to show alternative terms; use them only if they constitute part of the normal written form of the term (see ISO/IEC Directives Part 2:2011, D.4.7).



A definition shall consist of a single phrase specifying the concept. It shall be worded such that it can replace the term in context and shall not contain requirements. Additional information shall be given only in examples (which follow the same rules as Examples integrated in the text) or notes to entry (see ISO/IEC Directives Part 2:2011, D.4.8).


Notes to entry

Notes to entry follow different rules than notes integrated in the text: they are designated "Note # to entry:" and are numbered, starting at "1" in each terminological entry (a single note to an entry is numbered "1").


They provide additional information that supplements the terminological data and may, for example, give provisions relating to the use of a term, information regarding the units applicable to a quantity or an explanation of the reasons for selecting an abbreviated form as preferred term.


Footnotes to any part of a terminological entry shall not be used; put the information in a note to entry.


Terms from other sources

Do not create a new terminological entry if an appropriate entry exists in another authoritative source (e.g. ElectropediaInternational Electrotechnical Vocabulary, another standard, etc.). Instead, make a cross-reference to the source in the introductory sentence to the terms and definitions clause, or reproduce the terminological entry.

The source of repeated entries shall be cited after any notes to entry. Where the entry has been modified, the word “modified” shall be added together with a description of the modification (e.g. "SOURCE: IEC 60050-801:1994, 801-21-12, modified — Note 1 to entry has been added."). Such a source reference is informative.


International Electrotechnical Vocabulary (IEV)

The IEV (IEC 60050 series) is a general purpose multilingual vocabulary covering the field of electrotechnology, electronics and telecommunication (available at It comprises about 20 000 terminological entries, each corresponding to a concept. These entries are distributed among about 80 parts, each part corresponding to a given field.


The requirements for IEV terminological entries are specified in the IEC Supplement to the ISO/IEC Directives, Annex SK.


A special template ( exists for the preparation of IEV documents and can be downloaded from the IEC template page.



The following training materials are available:


Intended for persons familiar with the previous terminology rules [in the ISO/IEC Directives, Part 2, 2004 and Annex I to the IEC Supplement (IEV rules)] and who would just like to know the changes since 2011; the presentation refers to the examples in the companion document "Drafting terminology - Examples and explanatory notes".


Drafting terminology - Changes in rules
(MS Powerpoint)
downloadable file 2,7 MB
Provides an overview of the rules relating to the drafting of terms and definitions; the colour coding employed is reflected in the companion document "Drafting terminology - Examples and explanatory notes". Drafting terminology - Crib sheet external
downloadable file 100 kB
Provides examples of various terminological entries; the colour coding relates to that in "Drafting terminology - Crib sheet external". For use in a meeting, please note that the ppt contains notes explaining the rules related to the content of each slide. Drafting terminology - Examples and explanatory notes
(MS Powerpoint)
installation and user guide icon 2,3 MB



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