acronym

Word formed from the initial letters and/or syllables of other words, intended as a pronounceable abbreviation; for example, NATO (North Atlantic Treaty Organization), radar (radio detecting and ranging), RAM (random-access memory) and FORTRAN (formula translation). There are other forms of abbreviation.

Many acronyms are so successfully incorporated into everyday language that their origin as abbreviations is widely overlooked. Full stops are not normally used in acronyms.