hardwood

Preferred label: 

Wood produced from broad-leaved deciduous trees, varying widely in color and grain pattern; usually but not always harder than softwood. The examples that are most likely to be used as book boards on western European bindings are beech and oak, though other hardwoods can be found such as elm and chestnut.

AAT

The Arts and Architecture Thesaurus Online, The Getty Research Institute.

Additional reference: 
http://vocab.getty.edu/aat/300011916 (modified)
Hierarchy: 
Broader concept: 
Broader partitive concept: 
Top concept: 
materials
Getty AAT: