The Collaborative International Dictionary of English v.0.48:

citronwood \citronwood\ n.
   1. wood of a citron tree.
      [WordNet 1.5]

   2. a durable fragrant wood used in building (as in the roof
      of Cordova Cathedral); -- called also sandarac.

   Syn: sandarac.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

citronwood
    n 1: wood of a citron tree
    2: durable fragrant wood; used in building (as in the roof of
       the cathedral at Cordova, Spain) [syn: sandarac,
       citronwood]