interstice

Etymology

Old French interstice, from Latin interstitium.

noun

1. A small opening or space between objects, especially adjacent objects or objects set closely together, as between cords in a rope or components of a multiconductor electrical cable or between atoms in a crystal.
2. (figurative) A fragment of space.
   Relics of the British empire now mostly survive in the interstices of the global economy. They are the major winners from the fiscal haemorrhage that has resulted from financial globalisation. 14 August 2013, Simon Jenkins, “Gibraltar and the Falklands deny the logic of history”, in The Guardian, archived from the original on 2014-08-10
3. An interval of time required by the Roman Catholic Church between the attainment of different degrees of an order.
4. (by extension) A small interval of time free to be spent on activities other than one's primary goal.