RAS Syndrome

RAS syndrome (short for "redundant acronym syndrome syndrome") refers to the use of one or more of the words that make up an acronym in conjunction with the abbreviated form, thus in effect repeating one or more words. Two common examples are "PIN number" (the "N" in PIN stands for "number") and "ATM machine" (the "M" in ATM stands for "machine"). Other names for the phenomenon include PNS syndrome ("PIN number syndrome syndrome", which expands to "personal identification number number syndrome syndrome") or RAP phrases ("redundant acronym phrase phrases").

A person is humorously said to suffer from RAS syndrome when they redundantly use one or more of the words that make up an acronym or initialism with the abbreviation itself. Usage commentators consider such redundant acronyms poor style that is best avoided in writing, though they are common in speech. The degree to which there is a need to avoid pleonasms such as redundant acronyms depends on one's balance point of prescriptivism (ideas about how language should be used) versus descriptivism (the realities of how natural language is used). For writing intended to persuade, impress, or avoid criticism, usage guides advise writers to avoid pleonasm as much as possible, not because such usage is always "wrong", but rather because most of one's audience may believe that it is always wrong.

The term RAS syndrome is intentionally redundant, and thus an example of self-referential humor.

The term RAS syndrome was coined in 2001 by New Scientist. The similar term PNS syndrome was first used by Usenet users.

Other nonce coinages continue to arise. Select examples of RAS phrases include:

Although there are many instances in editing in which removal of redundancy improves clarity, the pure-logic ideal of zero redundancy is seldom maintained in human languages. As Bill Bryson says, "Not all repetition is bad. It can be used for effect [...], or for clarity, or in deference to . [...] 'SALT talks' and 'HIV virus' are [...] technically redundant because the second word is already contained in the preceding abbreviation, but only the ultra-finicky would deplore them. Similarly, in 'Wipe that smile off your face' the last two words are tautological—there is no other place a smile could be—but the sentence would not stand without them."

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