*marrow*

n. [ OE. marou, mary, maruh, AS. mearg, mearh; akin to OS. marg, D. merg, G. Mark, OHG. marg, marag, Icel. mergr, Sw. merg, Dan. marv, Skr. majjan; cf. Skr. majj to sink, L. mergere. √274 Cf. Merge. ] [ 1913 Webster ]

1. (Anat.) 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. [ 1913 Webster ]

2. The essence; the best part. [ 1913 Webster ]

It takes from our achievements . . .
The pith and marrow of our attribute. Shak. [ 1913 Webster ]

3. [ OE. maru, maro; -- perh. a different word; cf. Gael. maraon together. ] One of a pair; a match; a companion; an intimate associate. [ Scot. ] [ 1913 Webster ]

Chopping and changing I can not commend,
With thief or his marrow, for fear of ill end. Tusser. [ 1913 Webster ]

Marrow squash (Bot.), 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. (Anat.) See Spinal cord, under Spinal. [ 1913 Webster ]