An abbreviation (from Latin brevis - short) is a shortened form of a word or phrase that could also be written out in full. It is formed by a letter or group of letters taken from the corresponding word or phrase.
Abbreviations share some semantic and phonetic functions with acronyms or contractions, which are usually considered a subgroup of abbreviations. Yet abbreviations and acronyms are not exactly the same. A contraction is made by omitting certain letters or syllables of a word and bringing the initial and final letters or elements together. An abbreviation, in turn, may be created by omitting certain portions from the interior or by cutting off a part. Moreover, an acronym has a distinctive pronunciation, whereas an abbreviation is usually pronounced as the corresponding word. Yet in this report contractions and abbreviations are accounted as one unit.
Syllabic abbreviations may also be distinguished. These are abbreviations formed from first syllables of several words (e.g. Interpol = International + police). Syllabic abbreviation is considered a variant of the acronym. These are usually written in small letters, sometimes starting with a capital letter, and are always pronounced as words rather than letter by letter. Syllabic abbreviations should be distinguished from blends.
Common usage of abbreviation
Abbreviations are rarely used in formal writing. The ones that may be encountered are usually honorifics (e.g. Mr., Mrs., Miss, etc) or titles (e.g. Dr.).
The use of full stops in abbreviations should be noted. For example, in British English it is common to omit full stops in abbreviations which include the initial and final letters of a word (e.g. Mr, Mrs, Ms, Dr, St), whereas American usage favours it with full stops (e.g. Mr., Mrs., Ms., Dr., St.). A person's initials are usually followed by full stops as well (e.g. John D. Rockefeller, C. Aubrey Smith), although lately there has been a tendency...