An abbreviation is a shortened form of a word or phrase, by any method. It may consist of a group of letters or words taken from the full version of the word or phrase; for example, the word abbreviation itself can be abbreviated as abbr., abbrv., or abbrev.. It may also consist of initials only, a mixture of initials and words, or words or letters representing words in another language. Some types of abbreviations are acronyms or grammatical contractions or crasis.
Example of 15th-century Latin manuscript text with scribal abbreviations
Sign in New York City subway, reading "Penna." for Pennsylvania, showing American style of including the period even for contractions.
An acronym, a type of abbreviation, is a word or name consisting of parts of the full name's words. Some authorities add that an acronym must be pronounced as a single word rather than individual letters, so considering NASA an acronym but not USA; the latter they instead call an initialism or alphabetism, for a string of initial letters which are pronounced individually. Acronyms commonly are formed from initials alone, such as NATO, FBI, YMCA, GIF, EMT, and PIN, but sometimes use syllables instead, as in Benelux, NAPOCOR, and TRANSCO. They can also be a mixture, as in radar and MIDAS.
"NYPD", an initialism for "New York Police Department", used on the side of a police car
