third book of the Pentateuch, c.1400, from Late Latin Leviticus (liber), literally "book of the Levites," from Greek to Leuitikon biblion, from Leuites, from Hebrew Lewi. Properly the part of the Pentateuch dealing with the function of the priests who were of the tribe of Levi (a portion of the tribe acted as assistants to the priests in the temple-worship). The Hebrew title is Torath Kohanim, literally "the law of the priests." Related: Levite; Levitical.