in ‧ ter ‧ stice /ɪnˈtɜːstəs, ɪnˈtɜːstɪs $ -ɜːr-/ BrE AmE noun [countable usually plural] formal
[ Date: 1400-1500 ; Language: French ; Origin: Latin interstitus , past participle of intersistere 'to stand still in the middle' ]
a small space or crack in something or between things