Merriam-Webster Collegiate Dictionary - interstice

 noun  (plural ~s)  Etymology: Middle English, from Latin interstitium, from inter- + -stit-, -stes standing (as in superstes standing over) — more at superstition  Date: 15th century  1.  a. a space that intervenes between things; especially one between closely spaced things ~s of a wall  b. a gap or break in something generally continuous the ~s of society passages of genuine literary merit in the ~s of the ludicrous…plots — Joyce Carol Oates  2. a short space of time between events