Interstitial fluid, a solution which bathes and surrounds the cells of multicellular animals

Interstitial art, any work of art whose basic nature falls between, rather than within, the familiar boundaries of accepted genres or media

interstitial atom, an atom outside crystallographic lattice

Interstitial webpage, a web page that is displayed before an expected content page, often to display advertisements or confirm the user's age

Interstitial program, short television programming which is often shown between movies or other events

Interstitial cell (disambiguation)