NORTH ATLANTIC TREATY • DICTIONARY ONE.COM • Definition of North Atlantic Treaty

... is an abbreviation coined from the initial letter of each successive word in a term or phrase. In general, an acronym made up solely from the first letter of the major words in the expanded form is rendered in all capital letters (NATO from North Atlantic Treaty Organization; an exception would be ASEAN for Association of Southeast Asian Nations). In general, an acronym made up of more than the first letter of the major words in the expanded form is rendered with only an initial capital letter (Comsat from Communications Satellite Corporation; an exception ...

— The 2008 CIA World Factbook • United States. Central Intelligence Agency.