Abraham Gancwajch (1902–1943) was a prominent Nazi collaborator in the Warsaw Ghetto during the World War II occupation of Poland, and a Jewish kingpin of the ghetto underworld. Opinions about his ghetto activities are controversial, though modern research concludes unanimously that he was an informer and collaborator motivated chiefly by personal interest.

Hashomer Hatzair is a Labor Zionist, secular Jewish youth movement founded in 1913 in the Kingdom of Galicia and Lodomeria, Austria-Hungary, and it was also the name of the group's political party in the Yishuv in the pre-1948 Mandatory Palestine.