The term is used for training programs and agricultural centres in Europe and elsewhere.
At these centers Zionist youth and young adults would learn vocational skills necessary for their emigration to Israel and subsequent life in kibbutzim.
Nowadays, these programs are usually based on kibbutzim in Israel for youth who are in their gap year, between finishing high-school and starting university, and include exploring Israel and studying Israeli culture.
This was also true of the religious programs, that until a few decades were based on a religious kibbutz and typically contained a period of Torah study.
Nowadays, the religious programs still incorporate a period on a religious kibbutz, but are more diverse in what they offer, see at Bnei Akiva website (here).