EntityQ420986· pop 8U21Sign in to saveU21 or U-21 may refer to:Article3 sectionsContentsNaval vesselsOther usesSee alsoU21 or U-21 may refer to:== Naval vessels == , various vessels , a sloop of the Indian Navy , a submarine of the Austro-Hungarian NavyRead full article (4 paragraphs)ConnectionsBeechcraft King AirEntityUniversitas 21Entitygreat rhombihexahedronEntityGerman submarine U-21EntityCategoriesLetter–number combination disambiguation pages