3. Definitions of Terms

The format, style and content of documents containing Recommendations or Technical Reports should follow the basic principles and examples as described below in the section, 'Constructing a Terminology Entry in a Glossary'. These principles and examples are sufficiently complete that they can be used as guides in the construction of definitions of terms. The specific requirements for the format of definitions are also described below. If the document contains multiple definitions of terms, as in a glossary, it is particularly helpful if these are numbered individually and laid out in separate paragraphs for easy subsequent incorporation into later editions of the ‘Gold Book ’[ref. 1]. Definitions can be followed by separate explanatory notes and examples, as required.

In compiling a glossary, the current edition of the 'Gold Book' should be inspected in case a particular term has been defined previously within IUPAC. If it has, but there is a need to repeat the definition, then whenever possible the original wording should be retained. Whenever necessary, the definition should be reformatted to conform with the structure of a terminology entry given below. If it is considered essential to change the wording, e.g., if the original is too technical for a more general readership or if general terms need to be replaced by more specific ones for a narrower readership, then the changes made should be kept to a minimum and the justifying reasons given in a footnote, together with a reference to the original 'Gold Book' entry.

In certain areas, and particularly in metrology, it is important for IUPAC to retain consistency with definitions given by ‘higher authorities’ such as in the International Vocabulary of Basic and General Terms in Metrology [VIM; ref. 45] and the International Organization for Standardization [ISO; refs. 46 and refs. 48]. The definitions given by these bodies are agreed upon after much international consultation, and they have official status in connection with trade and/or legal usage. Again, any required rewordings for different usage should be specified and justified.

An IUPAC document should always fully list other sources that have been consulted for purposes of consistency. General references to the others sources consulted should be made within the document; more specific references need be given only when changes to the original are made as discussed above. The citation style for references should follow that given in PAC Instructions for Authors. References to other IUPAC documents should include the full title of the document.

Abbreviations, initialisms, and acronyms tend to be understood only by limited groups of practitioners. They should be used sparingly and always defined once in any document [the ‘Green Book’; ref. 3, section 9; also ref. 5]. In addition,each document should list separately all the abbreviations, initialisms, and acronyms in alphabetical order, with their full definitions, preferably in a table just ahead of the list of references. For the same reason, general laboratory slang, pertaining to a particular field, should not be used in written reports, as this will often not be understood by readers versed in related areas of chemistry, who nevertheless wish to gain an understanding of the new field.