Webster's Revised Unabridged Dictionary · 1913

Marrow

Marrow , noun

[Old English marou, mary, maruh, Anglo-Saxon mearg, mearh; akin to Old Saxon marg, Dutch merg, German Mark, Old High German marg, marag, Icelandic mergr, Swedish merg, Danish marv, Sanskrit majjan; compare Sanskrit majj to sink, Latin mergere. r274 Compare Merge.]

1.
(Anatomy) The tissue which fills the cavities of most bones; the medulla. In the larger cavities it is commonly very fatty, but in the smaller cavities it is much less fatty, and red or reddish in color.
2.
The essence; the best part.
It takes from our achievements... The pith and marrow of our attribute. — Shakespeare
3.
One of a pair; a match; a companion; an intimate associate. [Scottish]
Chopping and changing I can not commend, With thief or his marrow, for fear of ill end. — Tusser
Collocations (2)
Marrow squash (Botany) , a name given to several varieties of squash, esp. to the Boston marrow, an ovoid fruit, pointed at both ends, and with reddish yellow flesh, and to the vegetable marrow, a variety of an ovoid form, and having a soft texture and fine grain resembling marrow.
Spinal marrow (Anatomy) , See Spinal cord, under Spinal.

Marrow , transitive verb

To fill with, or as with, marrow or fat; to glut.