Nato [noun] [U not after the] - abbreviation for North Atlantic Treaty Organization (= an international military organization consisting of the US, Canada, Britain and 13 other European countries, formed in 1949 to improve the defence of Western Europe)The president's speech came at the opening session of the two-day NATO summit in Rome.
NATO
Meaning of NATO in English
Cambridge English vocab. Кембриджский английский словарь. 2012