The Collaborative International Dictionary of English v.0.48:

Leviticus \Le*vit"i*cus\ (-[i^]*k[u^]s), n. [See Levitical.]
   The third canonical book of the Old Testament, containing the
   laws and regulations relating to the priests and Levites
   among the Hebrews, or the body of the ceremonial law.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Leviticus
    n 1: the third book of the Old Testament; contains Levitical law
         and ritual precedents [syn: Leviticus, Book of
         Leviticus]