'Endosteum' definitions:

Definition of 'endosteum'

(from WordNet)
noun
Vascular membrane that lines the inner surface of long bones

Definition of 'Endosteum'

From: GCIDE
  • Endosteum \En*dos"te*um\, n. [NL., fr. Gr. ? + ? a bone.] (Anat.) The layer of vascular connective tissue lining the medullary cavities of bone. [1913 Webster]