The Main Intelligence Directorate (Soviet Union) (Russian: Гла́вное разве́дывательное управле́ние, tr. Glavnoye razvedyvatel'noye upravleniye, IPA: [ˈglavnəjə rɐzˈvʲɛdɨvətʲɪlʲnəjə ʊprɐˈvlʲenʲɪjə]), abbreviated GRU (Russian: ГРУ, IPA: [geeˈru]), was the foreign military intelligence agency of the Soviet Army General Staff of the Soviet Union.
Main Intelligence Directorate (Russian: Гла́вное разве́дывательное управле́ние, tr. Glavnoye razvedyvatel'noye upravleniye; IPA: [ˈglavnəjə rɐzˈvʲɛdɨvətʲɪlʲnəjə ʊprɐˈvlʲenʲɪjə]), abbreviated GRU (Russian: ГРУ; IPA: [geeˈru]), is the foreign military intelligence main directorate of the General Staff of the Armed Forces of the Russian Federation (formerly the Soviet Army General Staff of the Soviet Union). The official full name is Main Intelligence Directorate of the General Staff of the Armed Forces of the Russian Federation (Russian: Гла́вное разве́дывательное управле́ние Генера́льного шта́ба Вооружённых Сил Росси́йской Федера́ции). It is also known as GRU GSh (Russian: ГРУ ГШ; abbreviation of ГРУ Генера́льного шта́ба, tr. GRU Generalnovo Shtaba (English: GRU of the General Staff)).
More information on the English [1] and Russian [2] Wikipedia pages.