Acronyms and initialisms

Like abbreviations, acronyms are used to save space. Unlike abbreviations, they are often used within the body of a text to reduce repetition and improve flow. That said, too many acronyms can create an alphabet soup that is taxing for readers and can distract from your point. To avoid that, use unfamiliar acronyms sparingly, particularly in texts that already include a generous helping of familiar ones. For instance, as with abbreviations, there is generally no need to use an acronym when what it stands for is mentioned only once. Instead, write out the full term on first mention and, where applicable, use a shorter version thereafter. For example:

To ensure clarity and consistency, when you do use an acronym, use the full term on first mention, followed by the acronym to be used thereafter in brackets. On subsequent mention, use only the acronym. For example:

Acronyms that are common knowledge may be used directly without additional clarification. Examples:

Notwithstanding these general rules, in some cases it may be helpful to include an acronym, even when the full term it stands for is mentioned only once. For instance, in some texts you may wish to translate the name of a body or institution to facilitate comprehension for readers who do not speak the original language. However, there may not be an official English translation of that name and/or the name may be translated variously in different contexts. In such cases, including the original-language acronym is more precise and can be helpful for readers wishing to look for more information. For example:

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For certain formatting questions, it can be helpful to distinguish between acronyms and initialisms. Acronyms are formed from the first or first few letters of each of the words they are based on. They are pronounced as a word and do not take full stops or spaces. They are generally uppercased in full if 5 or fewer letters long and take only an initial cap if 6 or more letters long. Examples:

By way of exception, it is UOC policy to capitalize all letters in UNESCO and in the names of other organizations that choose to do so in their own official literature. For example:

Initialisms are formed from the first letter or letters of a series of words and are pronounced as the names of the individual component letters. They generally reflect the upper- or lowercasing used with the full term. They do not take spaces and, in BrE, when they consist entirely of uppercase letters, they do not take full stops. This is because the use of uppercase letters is thought to be sufficient to indicate that the word is a type of abbreviation. For example:

In contrast, when the full term that they are based on is written entirely in lower case, they usually do take full stops. For example:

Remember that e.g. and i.e. are not interchangeable: e.g. means for example, whereas i.e. means that is. It is UOC policy not to follow them with a comma. For example:

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Do not replicate foreign acronyms or initialisms in English unless the English versions are also widely used. Instead, use an English translation of the full term on first mention, followed by the source-language acronym to be used thereafter in brackets. Thus, DNI (document nacional d'identitat) should be left as is (e.g. the Spanish national identity document (DNI)), whereas IVA (from impost sobre el valor afegit) should be translated (i.e. VAT or value-added tax).

For longer terms that lack a well-established English equivalent, it may be possible to use a shortened English version of the full term for subsequent mentions instead of the source-language acronym. Thus, the Catalan Pla de recerca i innovació (PRI) could be rendered as the Catalan Research and Innovation Plan (PRI) on first mention and the PRI on subsequent mention, or it could be rendered the Catalan Research and Innovation Plan on first mention and referred to as simply the plan thereafter.

Foreign acronyms and initialisms in a foreign company's name, such as GmbH (Gesellschaft mit beschränkter Haftung) or SL (societat limitada), should always be left in the source language.

With regard to its own initialism, the UOC's policy is as follows: on first mention, use Universitat Oberta de Catalunya (UOC); on subsequent mention, use the UOC.

Certain other acronyms and initialisms often come up in texts related to Catalan universities. For instance, you may have come cross PDI (personal docent i investigador or teaching and research staff) or PAS (personal d'administració i serveis or administrative and service staff). For UOC-related texts, the rule of thumb in such cases is to write out the equivalent term in English in full and omit the corresponding Catalan acronym or initialism. For example, render PDC (personal docent col·laborador) as affiliated teaching staff and PRA (professor/a responsable d'assignatura) as coordinating professor. For more information on specific institutional nomenclature, see

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Just because an acronym uses capital letters, it does not mean that the words it is based on do. The use of capital letters in the referent will depend on the nature of the words themselves. Thus:

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As with Catalan, the plurals of English acronyms are not formed by doubling the letters (e.g. CCDD, TTAA).

Instead, they are formed by adding a final lowercase s (with no apostrophe). Example:

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The definite article the is not generally used with acronyms (e.g. NATO, not the NATO). In contrast, it is used with initialisms when it is also used with the referent when the referent is written in full. Examples:

Remember that for its own initialism, UOC-house style is the UOC. This is also true for many other Catalan university initialisms. Examples:

In contrast, many universities in English-speaking countries omit the article. Examples:

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The use of the indefinite article a or an is determined by the pronunciation of the acronym or initialism rather than the pronunciation of the words it is based on. Thus:

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The UOC house style includes the following preferences:


Write the initialisms AD (Anno Domini), CE (Common Era), BC (before Christ) and BCE (before the Common Era) in uppercase letters without spaces or full stops. Examples:

a.m. and p.m.

Write the initialisms a.m. (ante meridiem) and p.m. (post meridiem) in lowercase letters without spaces separated by full stops. Examples:

Remember a.m. is used for the first half of the day (from 12 midnight to 11.59 in the morning), while p.m. is used for the second half of the day (from 12 noon to 11.59 at night).

e.g. and i.e.

Write the initialisms e.g. (exempli gratia) and i.e. (id est) in lowercase letters without spaces and with full stops. Do not follow them with a comma. Examples:

Remember, e.g. and i.e. are not interchangeable: e.g. means for example, whereas i.e. means that is.


Use etc. only after a series of examples, not after a series of examples introduced by words or terms such as like, such as or e.g. Examples:

As a general rule, use etc. rather than an ellipse (“…”) to indicate an unfinished list. Use ellipses mainly to indicate halting or omitted speech. Also, it is not necessary to repeat the word etc. Examples:

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