marrow

Concise Oxford English Dictionary © 2008 Oxford University Press:
marrow/ˈmarəʊ/

▶noun

• 1 Brit. a long white-fleshed gourd with thin green skin, eaten as a vegetable.

• 2 the plant of the gourd family which produces this. [Cucurbita pepo.]

• 3 (also bone marrow) a soft fatty substance in the cavities of bones, in which blood cells are produced.

• 4 the vital part: such men were the marrow of the organization.

– phrases
to the marrow to one's innermost being.

– derivatives
marrowy adjective.

– origin OE mearg, mærg, of Gmc origin.