1the wood from a broadleaved tree (such as oak, ash, or beech) as distinguished from that of conifers:all hardwood should be treated with stain preservative [count noun]:their import of tropical hardwoods
[count noun] a broadleaved tree that produces hardwood:the land isn’t fertile enough for hardwoods [as modifier]:hardwood forests
2(in gardening) mature growth on shrubs and other plants: [as modifier]:hardwood cuttings are usually taken in winter
hardwood in other Oxford dictionaries
Definition of hardwood in the US English dictionary