An abbreviation (from Latin brevis, meaning short) is a shortened form of a word or phrase. It consists of a group of letters taken from the word or phrase. For example, the word abbreviation can itself be represented by the abbreviation abbr., abbrv., or abbrev.
In strict analysis, abbreviations should not be confused with contractions, crasis, acronyms, or initialisms, with which they share some semantic and phonetic functions, though all four are connected by the term "abbreviation" in loose parlance.An abbreviation is a shortening by any method; a contraction is a reduction of size by the drawing together of the parts. A contraction of a word is made by omitting certain letters or syllables and bringing together the first and last letters or elements; an abbreviation may be made by omitting certain portions from the interior or by cutting off a part. A contraction is an abbreviation, but an abbreviation is not necessarily a contraction. Acronyms and initialisms are regarded as subsets of abbreviations (e.g. by the Council of Science Editors). They are abbreviations that consist of the initial letters or parts of words.
Abbreviations have a long history, created so that spelling out a whole word could be avoided. This might be done to save time and space, and also to provide secrecy. Shortened words were used and initial letters were commonly used to represent words in specific applications. In classical Greece and Rome, the reduction of words to single letters was common. In Roman inscriptions, "Words were commonly abbreviated by using the initial letter or letters of words, and most inscriptions have at least one abbreviation." However, "some could have more than one meaning, depending on their context. (For example, A can be an abbreviation for many words, such as ager, amicus, annus, as, Aulus, Aurelius, aurum and avus.)"
Abbreviations in English were frequently used from its earliest days. Manuscripts of copies of the old English poem Beowulf used many abbreviations, for example 7 or & for and, and y for since, so that "not much space is wasted". The standardisation of English in the 15th through 17th centuries included such a growth in the use of abbreviations. At first, abbreviations were sometimes represented with various suspension signs, not only periods. For example, sequences like ‹er› were replaced with ‹ɔ›, as in ‹mastɔ› for master and ‹exacɔbate› for exacerbate. While this may seem trivial, it was symptomatic of an attempt by people manually reproducing academic texts to reduce the copy time. An example from the Oxford University Register, 1503: