10 Abbreviations and symbols
10.1 General principles
Abbreviations fall into three categories. Strictly speaking, only the first of these is technically an abbreviation, though the term loosely covers them all, and guidelines for their use overlap. There is a further category, that of symbols, which are more abstract representations.
• Abbreviations in the strict sense are formed by omitting the end of a word or words (Lieut., cent., assoc.).
• Contractions are formed by omitting the middle of a word or words (Dr, Ltd, Mrs, Revd, St). Informal contractions (I’ve, he’s, mustn’t) are widely used but are not always appropriate (
• Acronyms are formed from the initial letters of words. Acronyms are sometimes defined specifically as words formed from the initial letters of other words and pronounced as words themselves (AWOL, PIN, BOGOF), as opposed to initialisms, which are formed from the initial letters of words but not pronounced as words (BBC, QED). Some acronyms are now treated as orthodox nouns: examples include laser (from light amplification by stimulated emission of radiation) and scuba (self-contained underwater breathing apparatus). Another class can be presented in all caps or can retain just the initial capital: AIDS/Aids is an example. Oxford dictionaries, in particular the New Oxford Dictionary for Writers and Editors, give the meanings of a great many abbreviations. (
See also 10.2.4.)
• Symbols or signs may be letters assigned to concepts (π, Ω), or special typographical sorts (%, +, #). They are typically used in conjunction with words, numbers, or other symbols (πr2, £100, © Oxford University Press), although they may be used on their own as, for example, note markers.
In work for a general audience do not use abbreviations or symbols in open text (that is, in the main text but not including material in parentheses) unless they are very familiar indeed (US, BBC, UN), or would be unfamiliar if spelt out (DNA, SIM card), or space is scarce, or terms are repeated so often that abbreviations are easier to absorb. Abbreviations are more appropriate in parentheses and in ancillary matter such as appendices, bibliographies, captions, figures, notes, references, and tables, and rules differ for these.
It is helpful to spell out abbreviations at first mention, adding the abbreviation in parentheses after it:
It is generally better to avoid an abbreviation in a chapter title or heading but, if unavoidable, spell it out at the first mention in the text proper. Some house styles for specialist works make exception for abbreviations that are so familiar to a technical readership they do not need to be defined, such as RAM (random-access memory) in an academic computer book. It is helpful to authors and editors if the house style lists these exceptions. (See
It is not necessary to define an abbreviation at first mention in each chapter unless the book is likely to be read out of sequence, as in a multi-author work or a textbook. If this is the case, or simply if many abbreviations are used, including a list of abbreviations or a glossary is a good way to avoid repeatedly expanding abbreviations (see
For more on titles see
It is possible to refer to a recently mentioned full name by a more readable shortened form, rather than—or in addition to—a set of initials: the Institute rather than IHGS for the Institute of Heraldic and Genealogical Studies. (See also
As a general rule, avoid mixing abbreviations and full words of similar terms, although specialist or even common usage may militate against this, as in Newark, JFK, and LaGuardia airports.