The Palmach (Hebrew: פלמ"ח, an acronym for Plugot Mahatz (Hebrew: פלוגות מחץ), Strike Companies) was the regular fighting force of the Haganah, the unofficial army of the Yishuv (Jewish community) during the British Mandate of Palestine. It was established on May 15, 1941 and by the war of 1948 had grown to three fighting brigades and auxiliary aerial, naval and intelligence units. Being a Palmachnik (Palmach member) was considered not only as performing military duties, but also as a way of life. Significant leaders of the Palmach include Moshe Dayan, Yitzhak Sadeh, Yigal Allon and Yitzhak Rabin a future prime minister.
See more at Wikipedia.org...