(n) :
an
abbreviation formed by (usually initial)
letters taken from a word or series of words, and which is itself pronounced as a word, such as
RAM,
radar, or
scuba; sometimes contrasted with
initialism; a pronounceable word formed from the beginnings (letter or syllable) of other words and thus representing the phrase so formed, e.g. Benelux = the countries Belgium, Netherlands and Luxembourg considered as a political or economic whole