D defs.my
Entry 1 sense Webster, 1913

Interstitial

/ĭnˌ-tẽrs-tĭsh'-əl/ · In·ter·sti·tial · IPA /ɪntəɹˈstɪʃəl/
01 a. Of or pertaining to interstices; intermediate; within the tissues; as, interstitial cavities or spaces in the tissues of animals or plants.
  1. 1.
    Of or pertaining to interstices; intermediate; within the tissues; as, interstitial cavities or spaces in the tissues of animals or plants.