Bone Up Meaning

(intransitive, idiomatic) To study or cram, especially in order to refresh one's knowledge of a topic.

Example: 1913, William Christian Schmeisser, Are You Going To College?, page 132:
  Information acquired in that way, makes an impression ; this "boning" up for an examination is all right as a finishing touch, but it will not last.
1914, Kathleen Norris, Saturday's Child, ch. 2,
  Here's your chance to bone up on the segregating, or crediting, or whatever you call it.
2004, Kate Novack, "Fashion Literacy," Time, 14 Sep.,
  Now is the perfect time to bone up on your fashion history.