The Collaborative International Dictionary of English v.0.48:

Sandalwood \San"dal*wood\, n. [F. sandal, santal, fr. Ar.
   [,c]andal, or Gr. sa`ntalon; both ultimately fr. Skr.
   candana. Cf. Sanders.] (Bot.)
   (a) The highly perfumed yellowish heartwood of an East Indian
       and Polynesian tree (Santalum album), and of several
       other trees of the same genus, as the Hawaiian Santalum
       Freycinetianum and Santalum pyrularium, the Australian
       Santalum latifolium, etc. The name is extended to
       several other kinds of fragrant wood.
   (b) Any tree of the genus Santalum, or a tree which yields
       sandalwood.
   (c) The red wood of a kind of buckthorn, used in Russia for
       dyeing leather (Rhamnus Dahuricus).
       [1913 Webster]

   False sandalwood, the fragrant wood of several trees not of
      the genus Santalum, as Ximenia Americana, Myoporum
      tenuifolium of Tahiti.

   Red sandalwood, a heavy, dark red dyewood, being the
      heartwood of two leguminous trees of India (Pterocarpus
      santalinus, and Adenanthera pavonina); -- called also
      red sanderswood, sanders or saunders, and
      rubywood.
      [1913 Webster] Sandarach

WordNet (r) 3.0 (2006):

sandalwood
    n 1: close-grained fragrant yellowish heartwood of the true
         sandalwood; has insect repelling properties and is used for
         carving and cabinetwork