Definitions

1. noun

The central, older, and usually harder part of a tree’s trunk, containing the primary wood and often being more valuable than the sapwood.

“The furniture maker preferred to use the heartwood of the oak tree for its rich, dark color and durability.”

2. noun

A person’s innermost being or feelings, especially those that are deeply felt or strongly held.

“The heartwood of his character shone through in his selfless acts of kindness.”