Lying between.

part of speech: adjective

Pertaining to or containing interstices.

part of speech: adjective

Pert. to or containing interstices.

part of speech: adjective

Occurring in interstices or spaces; cells within tissues.

These interstitial cells form the interstitial gland. "The Glands Regulating Personality", Louis Berman, M.D..

So also there are the minor and interstitial trades that are still carried on by handicraft methods; these, too, are still somewhat loosely held in the fabric of the business system. "An Inquiry Into The Nature Of Peace And The Terms Of Its Perpetuation", Thorstein Veblen.

" If, for example, I were to say that you have interstitial keratitis, how would you be the wiser? "Round the Red Lamp Being Facts and Fancies of Medical Life", Arthur Conan Doyle.

Indeed, it may be said that there are very few, if any, rocks in which the chemical action of interstitial water has not formerly been, or is not at present being, carried on. "Geology", James Geikie.