The Collaborative International Dictionary of English v.0.48:

ilang-ilang \ilang-ilang\ n.
   1. An oil distilled from flowers of the ilang-ilang tree,
      used in perfumery.
      [WordNet 1.5]

   2. An evergreen Asian tree (Cananga odorata) with aromatic
      greenish-yellow flowers yielding a volatile oil; widely
      grown in the tropics as an ornamental.

   Syn: ylang-ylang, Cananga odorata.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

ilang-ilang
    n 1: oil distilled from flowers of the ilang-ilang tree; used in
         perfumery
    2: evergreen Asian tree with aromatic greenish-yellow flowers
       yielding a volatile oil; widely grown in the tropics as an
       ornamental [syn: ilang-ilang, ylang-ylang, Cananga
       odorata]