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Abbreviations are shortened forms of words or phrases that are used in place of the full form because they act as mnemonic aids and they save space.

Because they are mnemonic aids, abbreviations may be used without being fully understood. For example: people who know that BMW and IBM are abbreviations may not know the names being abbreviated, and, there may be no reason to know them. As an abbreviation becomes more successful, the full form becomes less useful, sometimes to a point where it falls into disuse.

From an index's point of view, a major problem with abbreviations is that not all of them are as successful as BMW and IBM. A few, such as CENTCOM (Central Command) become widely known for relatively brief periods of time. Many more, though, such as FARRP (forward area refueling and rearming point) and PETRONAS (Petroliam Nasional Bhd), are known only to limited audiences. Separate entries are needed for both forms if it is unclear which form is better known to members of the intended audience, as is frequently the case. Double-posting means that the space savings often attributed to abbreviations occur only in the text, and not in its index.

Decisions about indexing abbreviations are also affected by their type. There are three types of abbreviations:

1. Acronyms, which are pronounceable terms formed from the initial letters or groups of letters in a word or phrase. Examples include Anzac (Australia and New Zealand Army Corps), COBOL (COmmon Business Oriented Language) and snafu (situation normal all fouled up). Because they are pronounceable, many acronyms may end up being accepted as words or names in their own right, as happened with these and others such as AMEX (American Stock Exchange), gulag (Russian abbreviation for Chief Administration for Corrective Labor Camps), radar (radio detection and ranging) and sonar (sound navigation and ranging).

2. Initialisms, which are unpronounceable text strings formed from the initial letters of words in a phrase. When speaking, each letter in the initialism is pronounced separately. Examples include ASAP (as soon as possible), CPU (central processing unit), FBI (Federal Bureau of Investigation) and NTSB (National Transportation Safety Board).

3. Truncations, which are terms formed by truncating a word. Examples include ACK (acknowledgment) and AL (Alabama). Sometimes, a period is added to the truncated word, as in Prof. (professor) and Trans. (transactions).

Periods are points that appear at the end of some abbreviations, such as the two mentioned above. They are still common in truncations but they are seldom included today in acronyms and initialisms, which may also include a point following each letter in addition to a concluding period.

The points in acronyms and initialisms are sometimes followed by spaces, as in U. N. E. S. C. O.. Spaces probably are included in the acronyms and initialisms because they are used to separate the words in the phrase being abbreviated. Whether that is true or not, both points and spaces seem to be rapidly disappearing from all forms of abbreviations, including ones in which they were included in the past.

Guidelines for indexing abbreviations:

  • House style trumps all other guidelines, including those that follow. If you have doubts about what to do, ask your editor.
  • Post abbreviations as they appear in the text. Do not post them as if they had been spelled out in full and do not change orthographic conventions. For example: all the following are correct:

    Conrail for Consolidated Rail Corporation
    loran for long range navigation
    MoMA for Museum of Modern Art
    NACo for National Association of Counties
    NASA for National Aeronautics and Space Administration

    There is no reason to standardize orthography.
  • Punctuate abbreviations as they are punctuated in the text. If the text includes points, include them in the index. If punctuation varies in the text, use the form used most often or, when the convention has changed over time, use the form that is most current. For example: because it is now the official name of the organization, Unesco should be used in the index even if U.N.E.S.C.O. is used more often in the text.
  • Create two entries for abbreviations that are unlikely to be known by members of the intended audience. This includes abbreviations that are generally known only by specialists and abbreviations that the authors created specifically for use in their text. The two entries are: (1) An entry for the full form followed by the abbreviated form in parentheses - e.g., Mexican Tobacco (TABAMEX), and; (2) An entry for the abbreviation, - e.g., TABAMEX. If there are only a few locators, double-post them to both forms and qualify the abbreviation - e.g.,

    Mexican Tobacco (TABAMEX), 95, 141
    TABAMEX (Mexican Tobacco), 95, 141

    If there are many locators, post them with the full form and cross-reference it from the unqualified abbreviation - e.g.,

    TABAMEX. See Mexican Tobacco

    The number that tips the scale should be the number that is used elsewhere in the index to decide when undifferentiated locators should be replaced by subheadings.
  • Abbreviations widely known to the intended audience do not have to be qualified, even when they are used as main headings. For example: GATT alone is a suitable main heading when you can assume that nearly all members of the intended audience know it is an abbreviation for General Agreement on Tariffs and Trade.
  • Abbreviations that have been qualified in main headings do not have to be qualified in subheadings. For example:

    SDP (Social Democratic Party), ...
    welfare reform
        SDP position, ...

    Not repeating the qualifier also saves space.
  • Subheadings may include abbreviations that have not been used in main headings. For example: even if no main heading includes GDP,

        effect on GDP, ...

    is acceptable, assuming GDP is likely to be widely known by the intended audience. If not, gross domestic product should be spelled out in full.
  • Use the plural form of an abbreviation whenever you would use the plural form of what it represents. For example:

    LANs for local area networks
    MIA's for missing in action personnel
    NGOs for nongovernmental organizations
    URLs for universal resource locators

    are appropriate in both main headings and subheadings.
  • Use abbreviations that include spaces only as cross-references, and never as main headings. For example:

    U. N. E. S. C. O. See Unesco
    ulcers, ...
    unemployment, ...
    Unesco, ...
    unfamiliarity, ...

  • Cross-references do not have to be provided for all abbreviations used as main headings. In some cases, such as technical books, the audience may be expected to know the abbreviations. In others, the author may have used abbreviations as a way to help readers become more like subject matter experts. For example: the first time Perl appears in a text for novice programmers, the author is likely to note that it is an abbreviation for Practical Extraction and Report Language. The language's fully spelled-out name may never appear in the text again because experienced programmers refer to the language by its abbreviated name, and it ma never appear at all in a text for experienced programmers. No one familiar with programming is likely to use the fully spelled-out name as an access point. Therefore,

    Practical Extraction and Report Language. See Perl

    may be regarded as superfluous even in a book for novice programmers. Similarly,

    Strategic Arms Limitation Talks. See SALT

    may be superfluous in a book for foreign policy analysts and

    Experimental Prototype Community of Tomorrow. See EPCOT

    may be superfluous in a guidebook for tourists. Superfluity is a reflection of the intended audience. It is acceptable when space is not an issue, but it becomes unacceptable when it is.
  • When using cross-references, use them to point to the most common usage. For example: this,

    Bayerische Motoren Werke GmbH. See BMW
    personal computers. See PCs
    universal resource locators. See URLs

    not this,

    BMW. See Bayerische Motoren Werke GmbH
    PCs. See personal computers
    URLs. See universal resource locators

  • Locators and subheadings do not have to be always posted to both forms, or always posted to one to the exclusion of the other. For example: in a book for the general public, information about the International Business Machines Corporation should be posted under IBM rather than under the company's spelled-out name, but information about submarines should be posted under the spelled-out term rather than under the abbreviation SSBs (assuming it was mentioned in the text). Usefulness is more important than consistency. It, too, is a reflection of the intended audience.
  • Be consistent when there are alternative abbreviation schemes for a given data set. For example: in a given index, do not use alternative schemes when abbreviating the names of states, as has been done in this example:

    B.A. degree, ...
    Los Angeles (CA), ...
    PhD degree, ...
    Tulsa (Okla.), ...

    This is an instance where consistency improves usefulness.
  • Double-check abbreviations that include spaces. In word-by-word sorting, spaces between letters in an abbreviation will cause each letter to be treated as a word. Therefore, different headings that pertain to the same concept may not be sorted after one another, causing information to be distributed within the index rather than being consolidated by it. For example:

    U. N. E. S. C. O., ...
    ulcers, ...
    unemployment, ...
    U.N.E.S.C.O., ...
    unfamiliarity, ...

    As the index grows in size, distribution caused by inconsistent punctuation becomes harder to locate.
  • Alphabetize abbreviations as simple words, using the same system of alphabetization (letter-by-letter or word-by-word) used for other entries. Exceptions to this rule, such as alphabetizing St. in personal and place names or U.S. in organizational names as if they had been spelled out, were once common. Today, they are not supported by any national or international standard.

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Copyright © 2005 Martin Tulic. All rights reserved.