Definition of marrow

The word "marrow" derives from the Old English word "mæru," which was used to describe the soft, spongy substance found in the center of bones. The Old English word "mæru" is in turn derived from a Proto-Germanic root *marw-, which means "spongy" or "soft." The term "marrow" has evolved over the centuries to refer not only to the substance found in bones, but also to certain fruits and vegetables, such as the pulp of certain fruits like apples or pears, and the immature seeds or kernels of cereal grains. In cooking, the term "marrow" may also be used to describe the soft, custard-like flesh that forms inside the inside of a squash or pumpkin, which is edible and often cooked and eaten like a vegetable. Today, the word "marrow" continues to be used in both medical and culinary contexts, indicating the spongy, nutrient-rich core that lies at the heart of many organic materials.