heart of oak(redirected from heart-of-oak)
heart of oak
A trait said to belong to a very emotionally and/or mentally strong person. I don't know how a soldier does it—they must have a heart of oak. My brother has a heart of oak and has remained totally calm while coping with his wife's sudden illness.
heart of oaka courageous nature.
Literally, the heart is the solid central part of the oak tree traditionally used for timber for ships. The phrase was popularized by the words of an 18th-century song: ‘Heart of oak are our ships, Heart of oak are our men’.