RAS syndrome

Human language includes redundancy so that the brain can fill in gaps when something is misheard. Sometimes this redundancy gets in the way of rapid communication, causing people to make an abbreviation. But because there are only so many letters in the alphabet, sometimes these abbrevations can "collide", or have multiple independent meanings. Speakers may disambiguate the meaning by reintroducing a generic term following the abbreviation. The traditional use of trademarks as adjectives encourages this behavior as well. Still, some pedants consider this use of "RAS syndrome", or "redundant abbreviation syndrome syndrome", as poor style.

Examples

 * AC current
 * Alternating current, to distinguish from Animal Crossing, Armored Core, Asheron's Call, and Assassin's Creed


 * ATM machine
 * Automated teller machine, to distinguish from Asynchronous Transfer Mode


 * CSS style sheets
 * Cascading Style Sheets, to distinguish from Content Scramble System. (Compare the other DeCSS.)


 * FTP protocol
 * File Transfer Protocol, to distinguish from protest against law enforcement


 * IP protocol
 * Internet Protocol, to distinguish from the various exclusive rights that have been conflated under the intellectual property umbrella


 * LCD display
 * Liquid crystal display, to distinguish from lowest common denominator


 * PIN number
 * Personal identification number, to distinguish from "pin" or from some dialects' pronunciation of "pen"