HEARTWOOD
Meaning of HEARTWOOD in English
/ ˈhɑːtwʊd; NAmE ˈhɑːrt-/ noun
[ U ] the hard older inner layers of the wood of a tree
—compare sapwood
Oxford Advanced Learner's English Dictionary.
Оксфордский английский словарь для изучающик язык на продвинутом уровне.
2005