'Breastbone' definitions:

Definition of 'breastbone'

From: WordNet
noun
The flat bone that articulates with the clavicles and the first seven pairs of ribs [syn: sternum, breastbone]

Definition of 'Breastbone'

From: GCIDE
  • Breastbone \Breast"bone`\ (br[e^]st"b[=o]n`), n. The bone of the breast; the sternum. [1913 Webster]