Definition of "marrowbone"

marrowbone

noun
plural marrowbones
1. A bone containing edible marrow.
2. (humorous, chiefly in the plural) The shins or knees, chiefly in references to kneeling.
  Quotations
  Upon this condescension, the culprit was called up stairs[sic], and made acquainted with the mitigation of his fate; upon which he said, he would down on his marrow-bones to his own master, but would be damn'd before he would ask pardon of e'er a Frenchman in Christendom.
  1751, [Tobias] Smollett, chapter 56, in The Adventures of Peregrine Pickle […], volume II, London: Harrison and Co., […]
  So the news of the split between the old and the young one caused plenty of conversation, you may be sure; and will Mr. Robert go down on his marrowbones? and what has he done? was all the question.
  1861, Eneas Sweetland Dallas, Once a Week, volume 4, page 246
  They would all to a man have gone down on their marrowbones to him.
  1922 February, James Joyce, Ulysses, Paris: Shakespeare and Company, […]