An Etymological Dictionary of Astronomy and Astrophysics

1. A minute gap between the adjacent parts of a body or objects close together.
   

   2. In a crystal lattice, the empty space between adjacent atoms. The interstices are of two types: Tetrahedral-interstices and Octahedral-interstices. Also called → interstitial site.

Etymology (EN): From L. interstitium “space between; interval,” from intersistere, from → inter- “between,” + stem of stare “to stand,” cognate with Pers. istâdan, → stand

Etymology (PE): Andarjâ, literally “a place between,” from andar “between,” → inter-, + jâ, → place.