'Interstitial' definitions:

Definition of 'interstitial'

From: WordNet
adjective
Of or relating to interstices

Definition of 'Interstitial'

From: GCIDE
  • Interstitial \In`ter*sti"tial\, a. Of or pertaining to interstices; intermediate; within the tissues; as, interstitial cavities or spaces in the tissues of animals or plants. [1913 Webster]