The Collaborative International Dictionary of English v.0.48:

Tilia \Til"i*a\, n. [L., linden. Cf. Teil.] (Bot.)
   A genus of trees, the lindens, the type of the family
   Tiliaceae, distinguished by the winglike bract coalescent
   with the peduncle, and by the indehiscent fruit having one or
   two seeds. There are about twenty species, natives of
   temperate regions. Many species are planted as ornamental
   shade trees, and the tough fibrous inner bark is a valuable
   article of commerce. Also, a plant of this genus.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

Tilia
    n 1: deciduous trees with smooth usually silver-grey bark of
         North America and Europe and Asia: lime trees; lindens;
         basswood [syn: Tilia, genus Tilia]