Redundant Acronym Syndrome Syndrome. It's the phenomenon of using acronyms to describe a noun, when the noun is itself already in the acronym. A short list is included below.
ATM Machine (Automatic Teller Machine Machine), PIN Number (Personal Identification Number Number), RAID Array (Redundant Array of Independent Disks Array), AC/DC Current (Alternating Current/Direct Current Current), LAN Network (Local Area Network Network), RPG Game (Role Playing Game Game), ISBN Number (International Standard Book Number Number), HIV Virus (Human Immunodeficiency Virus Virus), and RAS Syndrome itself (Redundant Acronym Syndrome Syndrome).
The unfortunate affliction demonstrated when someone feels the need to state the last word of a 3 letter acronym, as if it wasnt part of the acronym in the first place.
I forgot my PIN number when I went to use the ATM machine!
(translation) I forgot my Personal Identification Number number when I went to use the Automatic Teller Machine machine!
You will note the irony of the Acronym itself, which stands for Redundant Acronym Syndrome syndrome, which is a RAS syndrome itself!