The Collaborative International Dictionary of English v.0.48:

Cubeb \Cu"beb\ (k[=u]"b[e^]b), n. [F. cub[`e]be (cf. It. cubebe,
   Pr., Sp., Pg., & NL. cubeba), fr. Ar. kab[=a]bat.]
   The small, spicy berry of a species of pepper (Piper
   Cubeba; in (Med.), Cubeba officinalis), native in Java and
   Borneo, but now cultivated in various tropical countries. The
   dried unripe fruit is much used in medicine as a stimulant
   and purgative.
   [1913 Webster]

WordNet (r) 3.0 (2006):

cubeb
    n 1: spicy fruit of the cubeb vine; when dried and crushed is
         used medicinally or in perfumery and sometimes smoked in
         cigarettes
    2: tropical southeast Asian shrubby vine bearing spicy berrylike
       fruits [syn: cubeb, cubeb vine, Java pepper, Piper
       cubeba]
    3: a cigarette containing cubeb [syn: cubeb, cubeb
       cigarette]