INTERSTITIAL

adj. located between the cells of other tissue (Anatomy); of a space between two objects; forming a space, forming a narrow opening

n. advertisement or promotion that is launched in a separate browser window while a requested WWW page loads (Internet)

Interstitial may refer to:Interstitial program, short television programming which is often shown between movies or other eventsInterstitial defect, a variety of crystallographic defectsInterstitial fluid, a solution which bathes and surrounds the cells of multicellular animalsInterstitial webpage, a web page that is displayed before an expected content page, often to display advertisements or confirm the user's ageInterstitial art, any work of art whose basic nature falls between, rather than within, the familiar boundaries of accepted genres or media
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Interstitial /in·ter·sti·tial/ pertaining to parts or interspaces of a tissue. in·ter·sti·tial adj. [more]Interstitial - Community and Resources

Adjective
1. of or relating to interstices
(pertainym) interstice

(a.)
Of or pertaining to interstices; intermediate; within the tissues; as, interstitial cavities or spaces in the tissues of animals or plants.