Definitionen
1.NounAn interstitial space within a tissue or organ.
2.NounSpecifically the tissue between the pulmonary alveoli and the bloodstream.
3.NounA state between systems or spaces.
4.NounAn interstice, the interval of time required by the Roman Catholic Church between the attainment of different degrees of an order (pluralised as interstitia for the overall policy, which is also occasionally spelled instertitia).