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 S. pyrularium, the Australian S. latifolium, etc. The name is extended to several other kinds of fragrant wood. [1913 Webster]

sandalwood, n.
1 the scented wood of a sandal-tree.
2 a perfume derived from this.

Idiom:
red sandalwood the red wood from either of two SE Asian trees, Adenanthera pavonina and Pterocarpus santalinus, used as timber and to produce a red dye. sandalwood oil a yellow aromatic oil made from the sandal-tree.

african sandalwood, red sandalwood, sandalwood family, sandalwood tree, true sandalwood