Abbreviated Coded Rendition of Name Yielding Meaning.
A.C.R.O.N.Y.M. is an acronym.
An abbreviation for a phrase created by taking the first letter or so of each word, AND is pronounced as a word itself.
"USA" is technically NOT an acronym, because people don't pronounce it as "You-Sah". However, "MADD" (Mothers Against Drunk Driving) is an acronym because it's pronounced exactly as it's spelled.