what is it called when you use abbreviations for words

We say we saw aUFO because, although the abbreviation begins with a 'U,' we pronounce the 'U' as if it were spelled 'yoo.' Thus we say we're going to a PTO meeting where an NCO will address us. Do we say an FBI agent or a FBI agent? Although 'F' is obviously a consonant and we would generally precede any word that begins with 'F' with a, we precede FBI with anbecause the first sound we make when we say FBI is not an 'f-sound,' it is an 'eff-sound.' One of the most often asked questions about grammar has to do with the choice of articles - a, an, the - to precede an initialism or acronym.

Do not italicize acronyms or initialisms even if they are the official title of a printed piece.Consider rewriting documents that are loaded with acronyms.Spell out the initialism or acronym on the first use (unless they are undoubtedly widely known, or are never used in their spelled out form) and follow with the abbreviation in parentheses to prepare readers for subsequent use of the abbreviation.Use initialisms and acronyms in moderation unless your readers are familiar with them.If you use CAD, do you mean Council of Associate Deans or computer-aided design? Be aware that familiarity with initialisms and acronyms is often context sensitive and field dependent. It is a good practice to limit initialisms and acronyms to situations where they add to your message. URL, when pronounced as three separate letters, 'U-R-L,' is an initialism for Uniform Resource Locator, but many people pronounce it as 'earl' or even 'yurl,' making it an acronym. AIDS is an acronym, while HIV is an initialism. FBI (Federal Bureau of Investigation) is an initialism. Thus NATO, pronounced NAY-tow, is an acronym for North Atlantic Treaty Organization, and LASER, pronounced LAY-zer, is an acronym for Light Amplification by Stimulated Emission of Radiation. The umbrella term abbreviation is used for acronyms and initialisms. Initialism refers to terms read as a series of letters. In precise usage, the word acronym refers only to terms based on the initial letters of their various elements and read as single words. The term acronym only dates from the 1940s and is derived from the Greek akros, meaning point, and onuma, meaning name. an unhappy tendency among amateur etymologists to derive words from the initials of proper names.'

What is it called when you use abbreviations for words