[1] : The Collaborative International Dictionary of English v.0.48

elder \el"der\, n. oe. ellern, eller, as. ellen, cf. lg.
   elloorn; perh. akin to ohg. holantar, holuntar, g. holunder;
   or perh. to e. alder, n. bot.
   a genus of shrubs sambucus having broad umbels of white
   flowers, and small black or red berries.
   1913 webster

   note: the common north american species is sambucus
         canadensis; the common european species s. nigra
         forms a small tree. the red-berried elder is s.
         pubens. the berries are diaphoretic and aperient. the
         european elder sambucus nigra is also called the
         elderberry, bourtree, old world elder, black
         elder, and common elder.
         1913 webster + wordnet 1.5

   box elder. see under 1st box.

   dwarf elder. see danewort.

   elder tree. bot. same as elder. --shak.

   marsh elder, the cranberry tree viburnum opulus.
      1913 webster
see also:
sambucus sambucus canadensis s. nigra s. pubens sambucus nigra elderberry 
bourtree old world elder black elder common elder box elder 
box dwarf elder danewort elder tree elder 
marsh elder viburnum opulus 

[2] : WordNet (r) 2.0

sambucus canadensis
     n : common elder of central and eastern north america bearing
         purple-black berries; fruit used in wines and jellies
         syn: american elder, black elderberry, sweet elder
see also:
american elder black elderberry sweet elder 

Sambucus >> S Words
Sambucus, definition of term: Sambucus
sambucus_pag1.html

Canadensis >> C Words
Canadensis, definition of term: Canadensis
canadensis_pag1.html