Aluf (Hebrew: אלוף, lit. "champion") is the term used in the Israel Defense Forces (IDF) for officers who in other countries would have the rank of general, air marshal, or admiral. In addition to the aluf rank itself, there are four other ranks which are derivatives of the word. Together, they constitute the five highest ranks in the IDF.
Aside from being a military rank, "Aluf" is used is a civilian context, particularly of sport, meaning "champion".
The term aluf comes from the Bible (אַלּוּף ’allūp̄): the Edomites used it as a rank of nobility, while the later books of the Tanakh use it to describe Israelite captains as well, e.g. Zachariah 9:7, 12:5-6, and later, for example Psalms 55:13, where it is used as a general term for teacher. It comes from a Semitic root meaning "thousand", making an ’allūp̄ the one who commands a thousand people. Strong however connects the word used to describe the Dukes of Edom, to a different root "alf" denoting a teacher and the root for the animal 'ox' from which the letter Aleph itself is derived, rather than eleph thousand, however they both comprise the same 3 letters.
The Israel Defense Forces (IDF) is an integrated force, ranks are the same in all services. It has a slightly compacted rank structure; for instance, the Chief of Staff (Ramatkal) is seemingly only equivalent to a lieutenant general (NATO OF-8) in other militaries. Rav aluf means 'arch-general', which would be equal to a field marshal or five star general in other armies and equivalent to OF-10.