Heartwood

[hɑ:twud]

解释:

(noun.) the older inactive central wood of a tree or woody plant; usually darker and denser than the surrounding sapwood.

埃斯特尔校对--From WordNet

解释:

(n.) The hard, central part of the trunk of a tree, consisting of the old and matured wood, and usually differing in color from the outer layers. It is technically known as duramen, and distinguished from the softer sapwood or alburnum.

费理斯编辑