Crevice
Crack, Gap, Opening
noun
すきま
隙 （すき） Crevice, Gap, Space, Chance, Fault, Room
隙間 （すきま） Crevice, Crack, Gap, Opening
間隔 （かんかく） Space, Interval, Gap
Yuri says 隙間 is for a physical Crevice, Crack, Gap, etc.
The schema すきま didn't account for Crevices.
There was a big Gap in the schema すきま