Anatomy . a soft, fatty, vascular tissue in the interior cavities of bones that is a major site of blood cell production.

the inmost or essential part

to pierce to the marrow of a problem.

strength or vitality

Fear took the marrow out of him.

rich and nutritious food.

Chiefly British . vegetable marrow.

noun

bottom , core , cream , essentiality , gist , kernel , meat , pith , quick , quintessence , quintessential , soul , spirit , stuff , substance , virtuality , essence , nub , root , essential , inmost , medulla , vitality