1. North temperate shrubs or trees having toothed leaves and conelike fruit; bark is used in tanning and dyeing and the wood is rot-resistant
   "Alder trees lined the banks of the stream, their roots helping to prevent erosion";
   - alder tree
    
2. Wood of any of various alder trees; resistant to underwater rot; used for bridges etc.
   "They used alder wood for the dock pilings due to its water resistance"

Derived forms: alders

Type of: tree, wood

Part of: Alnus, genus Alnus

Encyclopedia: Alder, Ontario