The form to which a word or phrase is reduced by contraction and omission; a letter or letters, standing for a word or phrase of which they are a part; as, Gen. for Genesis; U.S.A. for United States of America.
Abbreviations are the term given in typography to characters that are composed through the fusion of letters. One example of this is the character "&", which is a combination of the letters 'e' and 't' to form 'et' (Latin for 'and').
An abbreviation (from Latin brevis "short") is a shortened form of a word or phrase. Usually, but not always, it consists of a letter or group of letters taken from the word or phrase. For example, the word "abbreviation" can itself be represented by the abbreviation "abbr." or "abbrev."