RAS Syndrome

RAS Syndrome is Redundant Acronym Syndrome Syndrome. It's when an acronym is followed by a word that's also part of the acronym.

Some examples you may come across:

• ATM machine - Automated Teller Machine
• PIN number - Personal Identification Number
• ISBN number - International Standard Book Number
• PDF format - Portable Document Format
• LCD display - Liquid Crystal Display
• HIV virus - Human Immunodeficiency Virus
• DC Comics - Detective Comics
• RSVP please - Répondez S'il Vous Plaît — Reply please
• MLS soccer - Major League Soccer
• PAT testing - Portable Appliance Testing

While, in principle, the following word is redundant were we to spell out the acronym, that we tend to include it in everyday speech means it's usually serving a helpful function. Quite often, it's clarifying what you're talking about given many people won't know what the acronym actually stands for (see TLAs).

By the way, ATM is technically an initialism, while PIN is an acronym.

I'd guess you've probably come across RAS Syndrome, too. However, I didn't realise there was a name for it until recently, even though it was coined in New Scientist magazine back in 2001.

Also see acronym or initialism, TLAs, Capitonym, pleonasm