Which type of wood is classified as a 'hardwood'?

Oak is a hardwood. Hardwoods come from deciduous (broad-leaved) trees such as oak, maple, walnut, and cherry; they are generally denser, more durable, and used for furniture and flooring. Softwoods come from coniferous (evergreen) trees such as pine, cedar, spruce, and fir; they are typically lighter, easier to work, and used for framing and general construction. The hardwood/softwood classification is based on the type of tree, not strictly on how hard the wood feels. Knowing common examples of each — oak as a hardwood, pine as a softwood — is part of the materials topic.